Popular Science Monthly/Volume 4/January 1874/Growth and Decay of Mind


"And so from hour to hour we ripe and ripe,
And then from hour to hour we rot and rot,
And thereby hangs a tale."—As You Like It.

FEW subjects of scientific investigation are more interesting than the inquiry into the various circumstances on which mental power depends. By mental power I do not mean simply mental capacity, or the potential quality of the mind, but the actual power which is the resultant, so to speak, of mental capacity and mental training. The growth and development of mental power in the individual, and the process by which, after attaining a maximum of power, the mind gradually becomes less active, until in the course of time it undergoes at least a partial decay, form the special subjects of which I propose now to treat; but, in order to form clear ideas on these subjects, it will be necessary to consider several associated matters. In particular, it will be desirable to trace the analogy which exists between bodily and mental power, not only as respects development and decay, but with regard to the physical processes involved in their exercise.

It is now a well-established physiological fact that mental action is a distinctly physical process, depending primarily on a chemical reaction between the blood and the brain, precisely as muscular action depends primarily on a chemical reaction between the blood and the muscular tissues. Without the free circulation of blood in the brain, there can be neither thought nor sensation, neither emotions nor ideas. It necessarily follows that thought, the only form of brain-action which we have here to consider, is a process not merely depending upon, but in its turn affecting, the physical condition of the brain, precisely as muscular exertion of any given kind depends on the quality of the muscles employed and affects the condition of those muscles, not at the moment only, but thereafter, conducing to their growth and development if wisely adjusted to their power, or causing waste and decay if excessive and too long continued. It is important to notice that this is not a mere analogy. The relation between thought and the condition of the brain is a reality. So far as this statement affects our ideas about actually existent mental power, it is of little importance; for it is not more useful to announce that a man with a good brain will possess good mental powers than to say that a muscular man will be capable of considerable exertion. But as it is of extreme importance to know of the relation which exists between muscular exercise and the growth or development of bodily strength, so it is highly important for us to remember that the development of mental power depends largely on the exercise of the mind. There is a "training" for the brain as well as for the body—a real physical training—depending, like bodily training, on rules as to nourishment, method of action, quantity of exercise, etc.

When we thus view the matter, we at once recognize the significance of relations formerly regarded as mere analogies between mental and bodily power. Instead of saying that, as the body fails of its fair growth and development if overtaxed in early youth, so the mind suffers by the attempt to force it into precocious activity, we should now say that the mind suffers in this case in the same actual manner—that is, by the physical deterioration of the material in and through which it acts. Again, the old adage, "mens sana in corpore sano," only needs to be changed into "cerebrum sanum in corpore sano," to express an actual physical reality. The processes by which the brain and the body are nourished, as well as those which produce gradual exhaustion when either is employed for a long time or on arduous work, not only correspond with each other, but are in fact identical in their nature; so that Jeremy Taylor anticipated a comparatively recent scientific discovery when he associated mental and bodily action in the well-known apothegm, "Every meal is a rescue from one death and lays up for another; and while we think a thought we die." This is true, as Wendell Holmes well remarks, "of the brain as of other organs: the brain can only live by dying. We must all be born again, atom by atom, from hour to hour, or perish all at once beyond repair."

And here it is desirable to explain distinctly that the relations between mind and matter which we are considering are not necessarily connected with any views respecting the questions which have been at issue between materialism and its opponents. We are dealing here with the instrument of thought, not with that, whatever it may be, which sets the instrument in motion and regulates its operation. So far, indeed, as there is any connection between physical researches into the nature of the brain or its employment in thought, and our ideas respecting the individuality of the thinker, the evidence seems not of a nature to alarm even the most cautious. Thus, when Mr. Huxley maintains that thought is "the expression of molecular changes in that matter of life which is the source of our other vital phenomena," we are still as far as ever from knowing where resides the moving cause to which these changes are due. We have found that the instrument of thought is moved by certain material connecting links before unrecognized; but to conclude that therefore thought is a purely material process, is no more necessarily just than it would be to conclude that the action of a steam-engine depends solely on the eccentric which causes the alternation of the steam-supply. Again, we need find nothing very venturesome in Prof. Haughton's idea, that "our successors may even dare to speculate on the changes that converted a crust of bread, or a bottle of wine, in the brain of Swift, Molière, or Shakespeare, into the conception of the gentle Glumdalclitch, the rascally Sganarelle, or the immortal Falstaff," seeing that it would still remain unexplained how such varying results may arise from the same material processes, or how the selfsame fuel may produce no recognizable mental results. The brain does not show in its constitution why such differences should exist. "The lout who lies stretched on the tavern-bench," says Wendell Holmes, "with just mental activity enough to keep his pipe from going out, is the unconscious tenant of a laboratory where such combinations are being constantly made as never Wöhler or Berthelot could put together; where such fabrics are woven, such colors dyed, such problems of mechanism solved, such a commerce carried on with the elements and forces of the outer universe, that the industries of all the factories and trading establishments in the world are mere indolence, and awkwardness, and unproductiveness, compared to the miraculous activities of which his lazy bulk is the unheeding centre." Yet the conscious thought of the lout remains as unlike as possible to the conscious thought of the philosopher; nor will crusts of bread or bottles of wine educe aught from the lout's brain that men will think worth remembering in future ages.

Moreover, we must remember that we have to deal with facts, let the interpretation of these facts be what it may. The relations between mental activity and material processes affecting the substance of the brain are matters of observation and experiment. We may estimate the importance of such research with direct reference to the brain as the instrument of thought, without inquiring by what processes that instrument is called into action. "The piano which the master touches," to quote yet again from the philosophic pages of Holmes's "Mechanism in Thought and Morals," "must be as thoroughly understood as the musical box or clock which goes of itself by a spring or weight. A slight congestion or softening of the brain shows the least materialistic of philosophers that he must recognize the strict dependence of mind upon its organ in the only condition of life with which we are experimentally acquainted; and, what all recognize as soon as disease forces it upon their attention, all thinkers should recognize without waiting for such an irresistible demonstration. They should see that the study of the organ of thought, microscopically, chemically, experimentally, in the lower animals, in individuals and races, in health and in disease, in every aspect of external observation, as well as by internal consciousness, is just as necessary as if the mind were known to be nothing more than a function of the brain, in the same way as digestion is of the stomach."

In considering the growth of the mind, however, in these pages, it appears to me sufficient to call attention to the physical aspect of the subject, without entering into an account of what is known about the physical structure of the brain and the manner in which that structure is modified with advancing years. Moreover, I do not think it desirable, in the limited space available for such an essay as the present, to discuss the various forms of mental power; indeed, this is by no means essential where a general view of mental growth and decay is alone in question. Precisely as we can consider the development and decay of the bodily power without entering into a discussion of the various forms in which that power may be manifested, so we can discuss the growth of the mind without considering special forms of mental action.

Nevertheless, we cannot altogether avoid such considerations, simply because we must adopt some rule for determining what constitutes mental power. Here, indeed, at the outset, a serious difficulty is encountered. Certain signs of mental decay are sufficiently obvious, but the signs which mark the progress of the mind to its maximum degree of power, as well as the earlier signs of gradually diminishing mental power, are far more difficult of recognition. This is manifest when we consider that they should be more obvious, one would suppose, to the person whose mind is in question, than to any other; whereas it is a known fact that men do not readily perceive (certainly are not ready to admit) any falling off in mental power, even when it has become very marked to others. "I, the Professor," says Wendell Holmes in the "Professor at the Breakfast-table," "am very much like other men. I shall not find out when I have used up my affinities. What a blessed thing it is that Nature, when she invented, manufactured, and patented her authors, contrived to make critics out of the chips that were left! Painful as the task is, they never fail to warn the author, in the most impressive manner, of the probabilities of failure in what he has undertaken. Sad as the necessity is to their delicate sensibilities, they never hesitate to advertise him of the decline of his powers, and to press upon him the propriety of retiring before he sinks into imbecility." Notwithstanding the irony, which is just enough so far as it relates to ordinary criticism, there can be no question that, when an author's powers are failing, his readers, and especially those who have been his most faithful followers, so to speak, devouring each of his works as it issues from his pen, begin to recognize the decrease of his powers before he is himself conscious that he is losing strength. The case of Scott may be cited as a sufficient illustration, its importance in this respect being derived from the fact that he had long been warmly admired and enthusiastically appreciated by those who at once recognized signs of deterioration in "Count Robert of Paris," and "Castle Dangerous."

Yet judgment is most difficult in such matters. We can readily see why no man should be skilled to detect the signs of change in his own mind, since the self-watching of the growth and decay of mind is an experiment which can be conducted but once, and which is completed only when the mind no longer has the power of grasping all the observed facts and forming a sound opinion upon them. But it is even more natural that those who follow the career of some great mind should often be misled in their judgment as to its varying power. For, it must be remembered that the conditions under which such minds are exercised nearly always vary greatly as time proceeds. This circumstance affects chiefly the correctness of ideas formed as to the decay of mental powers, but it has its bearing also on the supposed increase of these powers. For instance, the earlier works of a young author, diffident perhaps of his strength, or not quite conscious where his chief strength resides, will often be characterized by a weakness which is in no true sense indicative of want of mental power. A work by the same author when he has made for himself a name, when he knows something of the feeling of the public as to his powers, and when also he has learned to distinguish the qualities he possesses—to see where he is strong and where weak—will have an air of strength and firmness not due, or only partially due, to any real growth of his mental powers. But, as I have said, and as experience has repeatedly shown, it is in opinions formed as to the diminution of mental power that the world is most apt to be deceived. How commonly the remark is heard that So-and-so has written himself out, or Such-a-one is not the man he was, when in reality, as those know who are intimate with the author so summarily dismissed, the deterioration, justly enough noted, is due to circumstances in no way connected with mental capacity! The author who has succeeded in establishing a reputation may not have (nay, very commonly has not) the same reason for exerting his powers to the full, as he had when he was making his reputation. He may have less leisure, more company, new sources of distraction, and so on. The earlier work, his chef-d'oeuvre, let us say, may have been produced at one great effort, no other subject being allowed to occupy his attention until the masterpiece had been completed—the later and inferior work, hastily accepted as evidence that the author's mind no longer preserves its wonted powers, may have been written hurriedly and piecemeal, and subjected to no jealous revision before passing through the press.

Here I have taken literary work as affording typical instances. But similar misapprehensions are common in other departments of mental work. For example, it is related that Newton, long before he was an old man, said of himself that he could no longer follow the reasoning of his own "Principia," and this has commonly been accepted as evidence that his mind had lost power. The conclusion is an altogether unsafe one, as every mathematician knows. It would have been a truly wonderful circumstance if Newton had been able, even only ten or twelve years after his magnum opus was completed, to follow its reasoning with satisfaction to his own mind—that is, with the feeling that he still had that grasp of the subject which he had possessed when, after long concentration of his thoughts upon it, he was engaged in the task of exhibiting a summary of his reasoning (for the "Principia" is scarcely more).

I can give more than one instance, in my own experience, of this seeming loss of mastery over a mathematical subject, while in reality the mind has certainly not deteriorated in its power of dealing with subjects of that particular kind. I will content myself with one. It happened that in 1869 I had occasion to examine a mathematical subject of no very great difficulty, but involving many associated relations, and requiring therefore a considerable amount of close attention. At that time I had made myself master, I think I may say without conceit, of that particular subject in all its details. Recently, I had occasion to resume the study of a part of the subject, in order to reply to some questions which had been asked me. Greatly to my annoyance, I found that I had apparently lost my grasp of it. The relations involved seemed more complex than they had before appeared to me; and I should there and then have dismissed the subject (not having leisure for mere mental experiments) with the feeling that my strength for mathematical inquiries had diminished. But the subject chanced to be one that I could not dismiss, for, though the questions directed to me might have been left unanswered, the time had come which I had assigned to myself (under certain eventualities then realized) for a complete restatement of my views, enforced and reiterated in every possible way, until a certain course depending upon them should have been adopted, or else the discussion of the matter rendered useless by lapse of time. I soon found, after resuming my study of the subject, that it was far more completely within my grasp than before—in fact, on reacquiring my knowledge of its details, the problems involved appeared to me as mere mathematical child's-play.

The great difficulty in judging of the growth and development of the mind consists in the want of any reliable measure of mental strength—any mental dynamometer, so to speak. Our competitive examinations are attempts in this direction, but very imperfect ones, as experience has long since shown. Neither acquired knowledge, nor the power of acquiring knowledge, is any true measure of mental strength. The power of solving mathematical problems is not necessarily indicative even of mathematical power, far less of general mental power. The ordinary tests of classical knowledge, again, have little real relation to mental strength. It may be urged that our most eminent men have, for the most part, been distinguished, at school or university, by either mathematical or classical knowledge, or both. This is doubtless true; but so it would be the case that they would have distinguished themselves above their fellows at public school or university if the heads of these establishments had in their wisdom set Chinese puzzling as the primary test of merit. The powerful mind will show its superiority (in general) in any task that may be assigned it; and, if the test of distinction is to be the skillful construction of Greek and Latin verse, or readiness in treating mathematical problems, a youth of good powers, unless he be wanting in ambition, will acquire the necessary qualifications even though he has no special taste for classical or mathematical learning, and is even perfectly assured that in after-life he will never pen a sapphic or set down an equation of motion.

In passing, I may note that nearly all our attempted measurements of mind depend too much on tests of memory. It is not recognized sufficiently that the part which memory plays in the workings of a powerful mind is subordinate. A good memory is a very useful servant; nothing more. In the really difficult mental processes, memory—at least what is commonly understood by the term—plays a very unimportant part. Of course a weak memory is an almost fatal obstacle to effective thought; but I am not comparing the worth of a good memory and a bad one, but of an average memory and one exceptionally powerful. I conceive that quite a large proportion of the most profound thinkers are satisfied to exert their memory very moderately. It is, in fact, a distraction from close thought to exert the memory overmuch; and a man engaged in the study of an abstruse subject will commonly rather turn to his book-shelves for the information he requires than tax his memory to supply it. The case resembles somewhat that of the mathematician who from time to time, as his work proceeds, requires this or that calculation to be effected. He will not leave the more engrossing questions that he has in his thoughts, to go through processes of arithmetic, but will adopt any ready resource which leaves him free to follow without check the train of his reasoning.

It would be perhaps difficult to devise any means of readily measuring mental power in examination or otherwise. The memory test is assuredly unsafe; but it would not be easy to suggest a really reliable one. I may remark that only those experienced in the matter understand how much depends on memory in our competitive examinations. Many questions in the examination-papers apparently require the exercise of judgment rather than memory; but those who know the text-books on which the questions are based are aware that the judgment to be written down in answer is not to be formed but to be quoted. So with mathematical problems which appear to require original conceptions for their solution: in nine cases out of ten such problems are either to be found fully solved in mathematical works, or others so nearly resembling them are dealt with that no skill is required for their solution.

I must confess that I am somewhat surprised to find Wendell Holmes, whose opinions on such matters are usually altogether reliable, recommending a test of mental power depending on a quality of memory even inferior to that usually in question in competitive examinations. "The duration of associated impressions on the memory differs vastly," he says, "as we all know, in different individuals. But in uttering distinctly a series of unconnected numbers or letters before a succession of careful listeners, I have been surprised to find how generally they break down, in trying to repeat them, between seven and ten figures or letters; though here and there an individual may be depended on for a larger number. Pepys mentions a person who could repeat sixty unconnected words, forward or backward, and perform other wonderful feats of memory; but this was a prodigy.[1] I suspect we have in this and similar trials a very simple mental dynamometer which may find its place in education." It appears to me, on the contrary, that tests of the kind should be as little used as may be. Memory will always have an unfair predominance in competitive examinations; but tests which are purely mnemonic, the judgment being in no way whatever called upon, ought not to be introduced, and should be discarded as soon as possible where already in use.[2]

It is worthy of notice that the growth of the mind is often accompanied by an apparent loss of power in particular respects; and this fact is exceedingly important, especially to all who desire to estimate the condition of their own mind. The mental phenomenon called (not very correctly) absence of mind is often regarded by the person experiencing it, and still more by those who observe it in him, as a proof of failing powers. But it often, if not generally, accompanies the increase of mental power. Newton displayed absence of mind much more frequently and to a much more marked degree when his powers were at their highest than in his youth, and not only did instances become much less frequent when he was at an advanced age, but the opposite quality, sensitiveness to small annoyances, began then to be displayed. Even an apparent impairment of the memory is not necessarily indicative of failing mental powers, since it is often the result of an increased concentration of the attention on subjects specially calling for the exercise of the highest forms of mental power—as analysis, comparison, generalization, and judgment. I have already noted that profound thinkers often refrain from exercising the memory, simply to avoid the distraction of their thoughts from the main subject of their study. But this statement may be extended into the general remark that the most profound students, whether of physical science, mathematics, history, politics, or, in fine, of any difficult subject of research, are apt to give the memory less exercise than shallower thinkers. Of course, the memory is exerted to a considerble degree, even in the mere marshaling of thoughts before theories can be formed or weighed. But the greater part of the mental action

devoted to the formation or discussion of theories is only indirectly dependent upon the exercise of memory.

Subject to the considerations suggested above, we may fairly form our opinion as to the general laws of the development of mind, by examining the lives of distinguished men and taking the achievement of their best work, that by which they have made their mark in the world's history, as indicative of the epoch when the mind had attained its greatest development. Dr. Beard, of New York, has recently collected some statistical results, which throw light on the subject of mental growth, though we must note that a variety of collateral circumstances have to be taken into account before any sound opinion can be formed as to the justice of Dr. Beard's conclusions. He states that "from an analysis of the lives of a thousand representative men in all the great branches of human effort, he had made the discovery that the golden decade was between thirty and forty, the silver between forty and fifty, the brazen between twenty and thirty, the iron between fifty and sixty. The superiority of youth and middle life over old age in original work appears all the greater, when we consider the fact that nearly all the positions of honor and profit and prestige—professorships and public stations—are in the hands of the old. Reputation, like money and position, is mainly confined to the old. Men are not widely known until long after they have done the work that gives them their fame. Portraits of great men are a delusion; statues are lies. They are taken when men have become famous, which, on the average, is at least twenty-five years after they did the work which gave them their fame. Original work requires enthusiasm. If all the original work done by men under forty-five were annihilated, the world would be reduced to barbarism. Men are at their best at that time when enthusiasm and experience are most evenly balanced; this period on the average is from thirty-eight to forty. After this period the law is that experience increases but enthusiasm declines. In the life of almost every old man there comes a point, sooner or later, when experience ceases to have any educating power."

There is much that is true, but not a little that is, to say the least, doubtful, in the above remarks. The children of a man's mind, like those of his body, are commonly born while he is in the prime of life. But it must not be overlooked that it is precisely because of the original work done in earlier life that a man as he grows older is commonly prevented from accomplishing any great amount of original work. Nearly the whole of his time is necessarily occupied in maturing the work originated earlier. And again, the circumstance that (usually) a man finds that the work of his earlier years remains incomplete and unsatisfactory, unless the labors of many sequent years are devoted to it, acts as a check upon original investigation. This remark has no bearing, or but slight bearing, on certain forms of literary work; but in nearly every other department of human effort men advanced in years find themselves indisposed to undertake original research, not from any want of power, but because they recognize the fact that sufficient time does not remain for them to bring such work to a satisfactory issue. They feel that they would have to leave to others the rearing of their mental offspring.

It cannot be questioned, however, that with old age there comes a real physical incapacity for original work, while the power of maturing past work remains comparatively but little impaired. Dr. Carpenter has shown how this may partly be explained by the physical changes which lead in old age to the weakening of the memory; or perhaps we should rather say that in the following passage his remarks respecting loss of memory serve to illustrate the loss of brainpower generally, and especially of the power of forming new ideas, in old age. "The impairment of the memory in old age," he says, "commonly shows itself in regard to new impressions; those of the earlier period of life not only remaining in full distinctness, but even it would seem increasing in vividness, from the fact that the eye is not distracted from attending to them by the continued influx of impressions produced by passing events. The extraordinary persistence of early impressions, when the mind seems almost to have ceased to register new ones, is in remarkable accordance with a law of nutrition I have formerly referred to. It is when the brain is growing that the direction of its structure can be most strongly and persistently" (query, lastingly) "given to it. Thus the habits of thought come to be formed, and those nerve-tracks laid down which (as the physiologist believes) constitute the mechanism of association, by the time that the brain has reached its maturity; and the nutrition of the organ continues to keep up the same mechanism in accordance with the demands upon its activity, so long as it is being called into use. Further, during the entire period of vigorous manhood, the brain, like the muscles, may be taking on some additional growth, either as a whole or in special parts; new tissue being developed and kept up by the nutritive process, in accordance with the modes of action to which the organ is trained. And in this manner a store of 'impressions' or 'traces' is accumulated, which may be brought within the 'sphere of consciousness' whenever the right suggesting strings are touched. But, as the nutritive activity diminishes, the 'waste' becomes more rapid than the renovation; and it would seem that, while (to use a commercial analogy) the 'old-established houses' keep their ground, those later firms, whose basis is less secure, are the first to crumble away—the nutritive activity which yet suffices to maintain the original structure not being capable of keeping the subsequent additions to it in working order. This earlier degeneration of later-formed structures is a general fact perfectly familiar to the physiologist."

One of the most remarkable features of mental development, characteristic, according to circumstances, of mental growth and of mental decay, is the change of taste for mental food of various kinds. Every one must be conscious of the fact that books, and the subjects of thought, lose the interest they once had, making way for others of a different nature. The favorite author, whose words we read and reread with continually fresh enjoyment in youth, appears dull and uninteresting as the mind grows, and becomes unendurable in advanced years. And this is not merely the effect of familiarity. I knew one who was never tired of reading the works of a famous modern novelist until the age of twenty-five or thereabouts, when it chanced that he was placed in circumstances which caused novel-reading to be an unfrequent occupation, and in point of fact certain works of this author were not opened by him for ten or twelve years. He supposed, when at the end of that time he took up one of these works, that he should find even more than the pleasure he formerly had in reading it, since the story would now have something of novelty for him, and he had once thoroughly enjoyed reading it even when he almost knew the work by heart. But he no longer found the work in the least interesting; the humor seemed forced, the pathos affected, the eloquence false; in short, he had lost his taste for it. In the mean time the works of another equally famous humorist had acquired a new value in his estimation.[3] They had formerly seemed rather heavy reading; now, every sentence gave enjoyment. They appeared now as books not to be merely tasted or swallowed, as Bacon hath it, but "to be chewed and digested." The change here described indicated (in accordance at least with the accepted estimates of the novelist and humorist in question) an increase of mental power. But a distaste for particular writings may imply the decay of mental power. And also, more generally, a tendency to disparagement is a very common indication of advancing mental age. "The old brain," says Wendell Holmes, "thinks the world grows worse, as the old retina thinks the eyes of needles and the fractions in the printed sales of stocks grow smaller."

Another singular effect of advancing years is shown by the tendency to repetition. It is worthy of notice that this peculiar mental phenomenon has been clearly associated with physical deterioration of the substance of the brain, because it may be brought about by a blow or by disease. Wendell Holmes, speaking of this peculiarity, remarks, "I have known an aged person repeat the same question five, six, or seven times, during the same brief visit. Everybody knows the archbishop's flavor of apoplexy in the memory as in the other mental powers. I was once asked to see a woman who had just been injured in the street. On coming to herself, 'Where am I? What has happened?' she asked. 'Knocked down by a horse, ma'am; stunned a little; that is all.' A pause, 'while one, with moderate haste, might count a hundred;' and then again, 'Where am I? What has happened?' "Knocked down by a horse, ma'am; stunned a little; that is all.'" (Mr. Holmes appears to have sympathized with the patient's mental condition.) "Another pause, and the same question again; and so on during the whole time I was by her. The same tendency to repeat a question indefinitely has been observed in returning members of those worshiping assemblies whose favorite hymn is 'We won't go home till morning.' Is memory then," he proceeds, "a material record? Is the brain, like the rock of the Sinaitic Valley, written all over with inscriptions left by the long caravans of thought, as they have passed year after year through its mysterious recesses? When we see a distant railway-train sliding by us in the same line, day after day, we infer the existence of a track which guides it. So, when some dear old friend begins that story we remember so well—switching off at the accustomed point of digression; coming to a dead stop at the puzzling question of chronology; off the track on the matter of its being first or second cousin of somebody's aunt; set on it again by the patient, listening wife, who knows it all as she knows her well-worn wedding-ring—how can we doubt that there is a track laid down for the story in some permanent disposition of the thinking-marrow?"

We seem to recognize here a process of change in the brain corresponding to that which takes place in the body with advancing years—the induration of its substance, so that it loses flexibility, and thus, while readily accomplishing accustomed work, is not readily adapted for new work. Our old proverb, "You can't teach an old dog new tricks," indicates, coarsely enough, but justly, the peculiarity, as well mental as bodily, to which I refer. There is not a loss of power, but a loss of elasticity. We see aged men working well in the routine work to which they have been accustomed, but failing where there is occasion for change either of method or of opinion. Again, one recognizes this peculiarity in the scientific worker, whence perhaps we may regard it as a fortunate circumstance that the tendency of the aged mind accords with its faculties, so that old men do not readily undertake new work. Perhaps no more remarkable instance could be cited of the combination I refer to—the possession of power on the one hand, and the want of elasticity on the other than the remarkable papers on the universe, written by Sir W. Herschel, in the years 1817 and 1818, that is, in his seventy-ninth and eightieth years. We find the veteran astronomer proceeding in the path which, more than forty years before, he had marked out for himself; but the very steadiness and strength of purpose with which he pursues it indicate the degree to which his mind had lost its wonted elasticity. In 1784 and 1785 he was traversing a portion of the same road. But then he was in the prime of his powers, and accordingly we recognize a versatility which enabled him to test and reject the methods of research which presented themselves to his mind. It was in those years that he invented his famous method of star-gauging, which our text-books of astronomy preposterously adopt as if it were an established and recognized method of scientific research. But Herschel himself, after trying it, and satisfying himself that it was unsound in principle, abandoned it altogether. In 1817 he adopted a method of research equally requiring to be tested, and, in my conviction, equally incapable of standing the test; but he now worked upon the plan he had devised, without subjecting it to any test. Nay, results which only a few years before he would certainly have rejected—for he did then actually reject results which were open to the same objection—passed muster in 1817 and 1818, and are recorded in his papers of those dates without comment. We may recognize another illustration of the loss of elasticity with advancing years, in the obstinacy, one may even say the perversity, with which Sir Isaac Newton, in the latter years of his life, adhered to opinions on certain points where, as has since been shown, he was unquestionably wrong, and where, had he possessed his former mental versatility, he must have perceived as much. Compare this with his conduct in earlier years, when for nineteen years he freely abandoned his theory of gravitation—though he had fully recognized its surpassing importance—simply because certain minute details were not satisfactorily accounted for. Many other instances might be cited, were it worth while, to show how the mind commonly changes when approaching an advanced age, in a manner corresponding to that bodily change—that stiffness and want of elasticity, without any marked loss of power—which comes on with advancing years. That old age does not necessarily involve any loss of power for routine work, has been clearly shown in the lives of many eminent men of our own era. The present Astronomer Royal for England affords a remarkable illustration of the fact, as also of the associated fact that new work is not easily achieved, nor an old mistake readily admitted or corrected at an advanced age.

It is well pointed out by Dr. Beard, in the lecture to which I have already referred, that "we must not expect to find at one age the mental qualifications due to another age—we must not look for experience and caution in youth, or for suppleness and versatility in age. We ought also to apportion to the various ages of a man the kind of work most suitable to them. Positions which require mainly enthusiasm and original work should be filled by the young and middle-aged; positions that require mainly experience and routine work, should be filled by those in mature and advanced life, or (as in clerkships) by the young who have not yet reached the golden decade. The enormous stupidity, and backwardness, and red-tapeism, of all departments of governments everywhere, are partly due to the fact that they are too much controlled by age. The conservatism and inferiority of colleges are similarly explained. Some of those who control the policy of colleges—presidents and trustees—should be young and middle-aged. Journalism, on the other hand, has suffered from relative excess of youth and enthusiasm."

Before passing from the lecture of Dr. Beard, I shall venture to quote the remarks which he makes on the evidence sometimes afforded of approaching mental decay by a decline in moral sensitiveness. "Moral decline in old age," he says, "means—'Take care; for the brain is giving way.' It is very frequently accompanied or preceded by sleeplessness. Decline of the moral faculties, like the decline of other functions, may be relieved, retarded, and sometimes cured by proper medical treatment, and especially by hygiene. In youth, middle age, and even in advanced age, one may suffer for years from disorders of the nervous system that cause derangement of some one or many of the moral faculties, and perfectly recover. The symptoms should be taken early, and treated like any other physical disease. Our best asylums are now acting upon this principle, and with good success. Medical treatment is almost powerless without hygiene. Study the divine art of taking it easy. Men often die as trees die, slowly, and at the top first. As the moral and reasoning faculties are the highest, most complex, and most delicate development of human nature, they are the first to show signs of cerebral disease. When they begin to decay in advanced life, we are generally safe in predicting that, if these signs are neglected, other functions will sooner or later be impaired. When conscience is gone, the constitution is threatened. Everybody has observed that greediness, ill-temper, despondency, are often the first and only symptoms that disease is coming upon us. The moral nature is a delicate barometer, that foretells long beforehand the coming storm in the system. Moral decline, as a symptom of cerebral disease, is, to say the least, as reliable as are many of the symptoms by which physicians are accustomed to make a diagnosis of various diseases of the bodily organs. When moral is associated with mental decline in advanced life, it is almost safe to make a diagnosis of cerebral disease.... Let nothing deprive us of our sleep. Early to bed and late to rise make the modern toiler healthy and wise. The problem for the future is to work hard, and at the same time to take it easy. The more we have to do, the more we should sleep. Let it never be forgotten that death in the aged is more frequently a slow process than an event; a man may begin to die ten or fifteen years before he is buried."

When mental decay is nearing the final stage, there is a tendency to revert to the thoughts and impressions of former years, which is probably dependent on the processes by which the substance of the brain is undergoing decay. The more recent formations are the first, as we have seen, to crumble away, and the process not only brings to the surface, if we may so speak, the earlier formations—that is, the material records of earlier mental processes—but would appear to bring those parts of the cerebrum into renewed activity. Thus, as death draws near, men "babble of green fields," as has been beautifully said, though not by Shakespeare, of old Jack Falstaff. Or less pleasant associations may be aroused, as we see in Mrs. Grandmother Smallweed, when "with such infantine graces as a total want of observation, memory, understanding, and intellect, and an eternal disposition to fall asleep over the fire and into it," she "whiled away the rosy hours" with continual allusions to money.

The recollections aroused at the moment of death are sometimes singularly affecting. None can read without emotion the last scenes of the life of Colonel Newcome. I say the last scenes, not the last scene only, though that is the most beautiful of all. Every one knows those last pages by heart, yet I cannot forbear quoting a few sentences from them. "'Father!' cries Clive, 'do you remember Orme's "History of India?"' 'Orme's History, of course I do; I could repeat whole pages of it when I was a boy,' says the old man, and began forthwith: "'The two battalions advanced against each other cannonading, until the French, coming to a hollow way, imagined the English would not venture to pass it. But Major Lawrence ordered the sepoys and artillery—the sepoys and artillery to halt, and defend the convoy against the Morattoes.' Morattoes, Orme calls them. Ho! ho! I could repeat whole pages, sir.'" Later, "Thomas Newcome began to wander more and more. He talked louder; he gave the word of command, and spoke Hindoostanee, as if to his men. Then he spoke words in French rapidly, seizing a hand which was near him, and crying, 'Toujours, toujours.' But it was Ethel's hand which he took.... Some time afterward, Ethel came in with a scared face to our pale group. 'He is calling for you again, dear lady,' she said, going up to Madame de Florac, who was still kneeling. 'And just now he said he wanted Pendennis to take care of his boy. He will not know you.' She hid her tears as she spoke. She went into the room, where Clive was at the bed's foot; the old man within it talked on rapidly for awhile; then again he would sigh and be still: once more I heard him say hurriedly, 'Take care of him when I'm in India,' and then with a heart-rending voice he called out, 'Léonore, Léonore!' She was kneeling at his side now. The patient's voice sank into faint murmurs; only a moan now and then announced that he was not asleep. At the usual evening hour the chapel-bell began to toll, and Thomas Newcome's hands outside the bed feebly beat time. And, just as the last bell struck, a peculiar, sweet smile shone over his face, and he lifted up his head a little, and quickly said, 'Adsum!' and fell back. It was the word we used at school when names were called, and lo, he, whose heart was as that of a little child, had answered to his name, and stood in the presence of The Master."

Sadder than death is it, however, when the brain perishes before the body. "How often, alas, we see," says Wendell Holmes, "the mighty satirist tamed into oblivious imbecility; the great scholar wandering without sense of time or place, among his alcoves, taking his books one by one from the shelves and fondly patting them: a child once more among his toys, but a child whose to-morrows come hungry, and not full-handed—come as birds of prey in the place of the sweet singers of morning. We must all become as little children if we live long enough; but how blank an existence the wrinkled infant must carry into the kingdom of heaven, if the Power that gave him memory does not repeat the miracle by restoring it!"—Cornhill Magazine.

  1. "This is nothing to the story told by Seneca of himself, and still more of a friend of his, one Portius Latro (Mendax it might be suggested), or to that other relation of Muretus, about a certain young Corsican." The note is Holmes's; but there are authenticated instances fully as remarkable as those here referred to. For instance, there is a case of an American Indian who could repeat twenty or thirty lines of Homer which had been read once to him, though he knew nothing of the Greek language. The power of repeating backward a long passage after it has been but once read is somewhat similar to that of repeating unconnected numbers, letters, or words This power has been possessed to a remarkable degree by persons in no way distinguished by general ability
  2. It may perhaps occur to the reader that I who write may object to mnemonic tests, because they would act unfavorably if they were applied to my own mental qualities. The reverse is, however, the case. I can recall competitive examinations in which I had an undue advantage over others because my memory chances to be very retentive in one particular respect: In its general nature my memory is about equal, I imagine, to the average, perhaps it is better than the average for facts, and rather below the average for what is commonly called learning "by heart:" but it is singularly retentive for the subject-matter of passages read overnight.
  3. Probably the best means of testing the development of one's own mind consists in comparing the estimate formed, at different times, of the value of some standard work. Of course different classes of writing should be employed to test different faculties of the mind. A good general test may be found in Shakespeare's plays, and perhaps still better in some of Shakespeare's sonnets. As the mind grows, its power of appreciating Shakespeare increases; and the great advantage of this particular test is, that the mind cannot overgrow it. It is like the standard by which the sergeant measures recruits, which will measure men of all heights, not failing even when giants are brought to be measured by it.