Page:Popular Science Monthly Volume 22.djvu/55

Rh, a woman with this organization suffers less—passes through all its stages safer, and recovers from its effects quicker and better—than those having any kind of a different organization. 3. In the matter of nursing offspring, which constitutes a very important part of childbearing, this healthy, well-balanced organization is very necessary. The fact that only about one half of the New England women can properly nurse their offspring is very significant of some change of organization—that there is a failure in the development of the mammary glands and the requisite power of the digestive organs—and this incapacity for nursing is constantly increasing. And, in the fourth place, the difference in the physical character of offspring is very significant. This is determined in a great measure by that of the mother. The more healthy and perfect her organization, and the better the balance of all her organs, the sounder and the more perfect will be the development of her offspring. The health and life of the child demand it.

This theory of human increase derives strong evidence from an analogous law in the animal and vegetable kingdoms. It is well known that great improvements have been made within the present century in domestic animals, and this, too, by the application of physiological laws. To such an extent have the results of observation and experiment been here carried, that this process of change and improvement has been reduced almost to a science. The terms here used—"pure blood," "thorough-bred," "pedigree," "breeding in-and-in," and "cross-breeding"—may all be explained by two great leading principles. One is a general law of propagation, based upon a perfect standard; and the other is the law of inheritance, subject to certain conditions. The three first-named terms have originated more from an observance or carrying out the first law—breeding from the best stock; but the two latter terms depend more upon the effects of inheritance. The results of the experiments in improving domestic stock indicate clearly that there must be some settled rules or laws in the process; and, if so, is there not some great general law governing and controlling all others? A similar law of propagation exists in vegetable physiology. It is a fact well attested by gardeners that, in order to produce flowers and fruit, the soil must not be too rich nor too poor; if the plant or tree grows too luxuriously, its branches or roots must be pruned; while, on the other hand, if unthrifty, it must receive better culture and its roots be enriched before it will become fruitful. It is well understood by gardeners that, in order to raise the best fruit and vegetables, the fairest and best-looking seed must be selected. So in setting out plants and trees the best-looking and well balanced specimens are always selected. Other facts and illustrations might be cited from this source to prove that some general law governed in the growth and changes of organic life.

Again, arguments in favor of a general law of increase may be