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115
CORRESPONDENCE.

dies. In a country like ours," he would add in a whisper, "the introduction of such a system might prove murderous to some civilized beings."

Dr. Black complains of my superciliousness in preferring a charge of ignorance against a contemporary who has for a long series of years anxiously sought the solution of "the problem how the sick can be made well." Sad enough; but that is no reason why I should withdraw my charge. Dr. Black may have sought that solution for a most venerable series of years, but, unless he holds his own time as cheap as that of your readers, he ought to seek it more anxiously than ever, for it is very evident that he has not yet found it.

Felix L. Oswald.

 

 

THE GEOLOGICAL DISTRIBUTION OF FORESTS.

Messrs. Editors:

IN discussing "The Geological Distribution of North American Forests," in your August number (pp. 521, 522), Mr. Thomas J. Howell makes the general statement that the loess (or lacustral deposits) of the campestrian province "is devoid of trees," except where cut through by erosion; from which he infers that "the loess is not capable of sustaining forest-growths for any length of time." By way of explanation, he adds that the loess "evidently was timbered during the time that part of it was covered by lakes and marshes," but, "when the great rivers cut their beds down to nearly their present level, the timber gradually died out." To generalization, inference, and explanation, exception must alike be taken.

In much of Eastern Iowa, and in Southeastern Minnesota, the loess is confined to an irregular zone, five to fifty miles wide, flanking the deeply eroded valley of the Mississippi on the west, and overlapping the glacial drift which forms the greater part of the surface of both States. The western limit of this zone is exceedingly sinuous; lobes of drift extend for miles within its general area, and narrow, finger-like belts of loess, sometimes separating into isolated outliers, extend still farther upon the drift-plain. Now, this drift-plain is quite timberless; but the loess is naturally wooded to its extreme margin, and its outliers are also generally wooded. The coincidence of forest-growth with loess is indeed so perfect in this region that maps showing the wooded area indicate with almost equal accuracy the loess area. This is a region, too, in which not only the "great rivers," but many of their minor tributaries, have cut their channels through the loess, and far into the subjacent rocks, thus developing the picturesque river bluffs which lure so many tourists to the upper Mississippi region. A parallel relation between loess and forests obtains in Central and Southern Illinois. Here the loess first appears, in passing from north to south, as isolated mounds rising from the almost dead-level drift-plain; which mounds, however far from other forests, are well wooded. The Missouri River loess-belt is, it is true, generally treeless, except along water-ways, which may or may not, however, cut through its deposits; but natural timber is far more abundant than over contiguous drift-areas, while its capability of supporting arborescent vegetation is emphatically attested by the unprecedented growth of artificially-planted fruit and forest trees, which is at once the marvel of Eastern and the boast of Western horticulturists. The potent influence of geological structure in determining the flora of any region is demonstrated by these relations of loess and forests, especially in Northeastern Iowa; but the connection is directly opposite from that which Mr. Howell seeks to establish.

But other and equally significant relations exist. Thus, it has been repeatedly pointed out by the director of the Iowa Weather Service, Dr. Gustavus Hinrichs, that the lines of equal timber in Eastern Iowa correspond remarkably, though in a general way, with the lines of equal rainfall.

Again, the origin of the loess is yet a mooted point in geology, and the declaration that its surface was once marshy is scarcely warranted; while no unequivocal evidence that it was ever more heavily or continuously wooded than now has ever been adduced.

The question as to the distribution of forests, particularly in the campestrian province, is inextricably involved with that of the treelessness of the prairies, concerning which so much has been written, but concerning which it is evident (since neither of the relations pointed out in this note have ever been adequately considered by those who have addressed themselves to the problem) that the last word has not yet been spoken. Mr. Howell would sever the Gordian knot at a stroke; but certainly some of its strands have escaped his blade.

Yours, W. J. McGee.
Washington, D. C., July 24, 1883.
 

 

INFANTILE DYSPEPSIA.

Messrs. Editors:

Referring to the very interesting passage at arms between Dr. Oswald, representing the natural, and Dr. Black, the anti-natural school of medicine, while not desiring to provoke further controversy, I beg leave to offer a few remarks upon one point at issue, viz., that pertaining to the alimentation of infants. Dr. Black (see October