Page:Popular Science Monthly Volume 33.djvu/500

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When we survey the different kinds of water-provision among the mosses, we are struck with the variety of ways of adaptation that have been developed for the attainment of the same end. In so small plants, the demands upon the efficiency of the water-bearing apparatus are likewise quite small, and the choice among them is only slightly limited. The larger the plant-forms become, the greater the demands made upon the water-bearing system, the more plainly appears the diversified efficiency of the adaptation henceforth possible, till at last there remains to Nature a single available model, which she applies with certain variations everywhere that large, stately plant-forms are produced.—Translated for the Popular Science Monthly from Humboldt.

By WALTER B. PLATT, M. D., F. R. C. S. (Eng.).

WE do not intend to discuss in this paper the subjects of bad ventilation and impure air, imperfect drainage, damp cellars, or insufficient nourishment. Residents of the country may suffer from all these as well as dwellers in cities. There are, however, certain injurious influences more insidious in their operation, which are peculiar to cities, and affect the well-to-do as well as the poor, although not in equal degree. I believe these lead, sooner or later, to degeneration of the individual and his offspring, by producing progressive feebleness, and to ultimate extinction of such families as are long subjected to their force. I refer to those which chiefly affect the stability of the nervous system, rendering it less capable of sustained work, and, in a secondary way, only the circulation and general nutrition. The end-result of all these influences is to lessen the producing power of each man, and thus to depreciate his value as an economic factor. They ought not to exist if their removal be possible, and if it can be effected without greater expense than their ill effects warrant. Their cause is to be found in faulty municipal arrangements which can be largely corrected by intelligent action and supervision. They work by producing insomnia, aberrant forms of mental action, singling out those who are less strong as subjects of the so-called neurasthenia.

These effects accumulate with each successive generation subjected to their influence, until the final inheritor finds the load too heavy to bear and do any useful work. The ne'er-do-wells and idlers are often, not always, such, from actual inability for persistent effort. Let us see if such influences exist, if they are injurious