Page:Popular Science Monthly Volume 17.djvu/270

258 naked bodies, their unwieldy, disproportionate abdomina, and their heads too heavy for their necks to support, we could not but marvel."

Davy and Whewell might, further, have found in Erasmus Darwin's "Zoönomia" some remarks on the different stages of maturity which animals of different species have reached when they are first brought into the world. The author uses these very words: "The chicks of the pheasant and the partridge have more perfect plumage, more perfect eyes, and greater aptitude for walking, than the callow nestlings of the dove or the wren. It is only necessary to show the first their food and teach them how to pick, while the latter for days obtrude a gaping mouth." Would it have been too much trouble for a man of such extensive reading as Professor Whewell to have run his eyes over the passage above quoted? Being, moreover, a German scholar—at least to the extent of an occasional mistranslation from the language the Professor might have read that Lorenz Oken divided the class Birds into two main subdivisions, nest-sitters and nest-quitters (nest-hocker und nest-flüchter), according as when hatched they remain helpless in the nest, or are at once able to run about and seek food for themselves.

Davy, by the mouth of "Ornither," gives a very lame explanation of the fact that the majority of birds can not fly as soon as hatched. Before they can take flight they have to await not alone the growth of their wing-feathers, but the simultaneous development of the muscles. The Raptores, Passeres, etc., are, as we have already seen, unable to walk as well as fly. Does this inability depend upon the want of feathers? The fact that parent-birds educate their young is clearly established by the interesting observations of Dr. C. Abbott.

In the case of birds of prey the process of education is somewhat prolonged, even after leaving the nest. It is thought by many that Deuteronomy xxxii., v. 11, is a description of the manner in which eagles train their young to fly; "stirring up" the nest, i. e., shaking and disturbing it so as to compel the nestlings to leave their cradle; "fluttering" over them "and bearing them on her wings"—that is to say, following and intercepting their downward movement, and aiding them to reascend.

Thus we see that the condition of the young of the lower animals is, after all, analogous to that of the human infant. The child, indeed, is still slower in learning to walk than the kitten or the young ape, not because he has to learn in a different manner, but because the development of his muscles and joints is much more gradual; because his head is relatively heavier; because he has to support himself on one pair of limbs only, thus rendering his base much narrower and his center of gravity higher from the ground; and because, as we have already pointed out in the case of the kitten, the hinder extremities gain strength more slowly than the anterior.