practical observation. We can hardly doubt that man attained at an early day to that conception of identity and of difference which Plato places at the head of his metaphysical system. We shall urge presently that it is precisely such general ideas as these that were man's earliest inductions from observation, and hence that came to seem the universal and "innate" ideas of his mentality.
It is quite inconceivable, for example, that even the most rudimentary intelligence that could be called human could fail to discriminate between living things and such inanimate structures as the rocks of the earth. The most primitive intelligence, then, must have made a tacit classification of the natural objects about it into the grand divisions of animate and inanimate nature. A step beyond this—a step, however, that may have required centuries or millenniums in the taking—must have carried man to a plane of intelligence from which a primitive Aristotle or Linnæus was enabled to note differences and resemblances connoting such groups of things as fishes, birds, and furry beasts. This conception, to be sure, is an abstraction of a relatively high order. We know that there are savage races to-day whose language contains no word for such an abstraction as bird or tree. We are bound to believe, then, that there were long ages of human progress during which the highest man had attained no such stage of abstraction; but, on the other hand, it is equally little in question that this degree of mental development had been attained long before the opening of our historical period. The primeval man, then, whose scientific knowledge we are attempting to predicate, had become, through his conception of fishes, birds, and hairy animals as separate classes, a scientific zoologist of relatively high attainments.
In the practical field of medical knowledge a certain stage of development must have been reached at a very early day. Even animals pick and choose among the vegetables about them, and at times seek out certain herbs quite different from their ordinary food, practising a sort of instinctive therapeutics. The cat's fondness for catnip is a case in point. The most primitive man, then, must have inherited a racial or instinctive knowledge of the medicinal effects of certain herbs; in particular he must have had such elementary knowledge of toxicology as would enable him to avoid eating certain poisonous berries. Coupled with his knowledge of things dangerous to the human system there must have grown up at a very early day a belief in the remedial character of various vegetables as agents to combat disease. Here, of course, was a rudimentary therapeutics; the crude principle of an empirical art of medicine.
It must be recalled, however, that primitive medicine was not a matter of drugs so much as a matter of incantations. Therapeutics belonged at first rather to the domain of religion than to that of science. For disease was not, in all probability, thought of at first as a "natural" phenomenon, but always as a result of the occult influence of an enemy. A study of this question leads us to some very curious inferences. The more we look into the matter, the more the thought forces itself home to us that the idea of natural death, as we now conceive it, came to primitive man as a relatively late scientific induction. This thought seems almost startling, so axiomatic has the conception "man is mortal" come to appear. Yet a study of the ideas of existing savages, combined with our knowledge of the point of view from which historical peoples regard disease, makes it more than probable that the primitive conception of human life did not include the idea of necessary death. We are told that the Australian savage who falls from a tree and breaks his neck is not regarded as having met a natural death, but as having been the victim of the magical practices of the "medicine-man" of some neighboring tribe. Similarly, we find that the Egyptian and the Babylonian of the early historical period conceived illness as being almost inevitably the result of the machinations of an enemy. One need but recall the superstitious observances of the Middle Ages and the yet more recent belief in witchcraft to realize how generally disease has been personified as a malicious agent invoked by an unfriendly mind. Indeed, the phraseology of our present-day speech is still reminiscent of this; as when, for example, we speak of an "attack" of fever and the like.
