Page:Popular Science Monthly Volume 21.djvu/495

Rh strength at least. As the existing pearly nautilus is the sole survivor of the immense hordes of four-gilled and shelled cuttle-fishes which swarmed in the primitive seas and oceans of our earth, or as the few living "lampshells," or Brachiopods, represent in themselves the fullness of a life that crowded the Silurian seas, so the two existing species of elephants with which we are familiar to-day stand forth among quadrupeds as the representatives of a comparatively plentiful past population of these mammalian giants. The causes which have depopulated the earth of its elephantine tenants may be alluded to hereafter; but it is evident that neither size nor strength avails against the operation of those physical environments which so powerfully affect the ways and destinies of man and monad alike. One highly important feature of elephant organization may, however, be noted even in these preliminary details respecting the modern scarcity of elephantine species, namely, that the slow increase of the race, and, as compared with other animals at least, the resulting paucity of numbers, must have had their own share as conditions affecting the existence of these huge animals. The elephants are, of all known animals, the slowest to increase in numbers. At the earliest, the female elephant does not become a parent until the age of thirty years, and only six young are capable of being produced during the parental period, which appears to cease at ninety years of age; the average duration of elephant-life being presumed to be about a hundred years. But it is most interesting, as well as important, in view of any speculation on the increase of species and on the question of competition among the races of animal life, to reflect that, given favorable conditions of existence, such as a sufficiency of food, a freedom from disease and from the attack of enemies, and the elephant race, slow of increase as it is, would come in a few thousand years to stock the entire world with its huge representatives. On the data afforded by the foregoing details of the age at which these animals produce young, and of their parental period, it is easy to calculate that in from seven hundred and forty to seven hundred and fifty years, nineteen million elephants would remain to represent a natural population. If such a contingency awaits even a slowly increasing race such as the elephants unquestionably are, the powerful nature of the adverse conditions which have ousted their kith and kin from a place among living quadrupeds can readily be conceived. In the face of such facts, the contention that the "struggle for existence," in lopping off the weak and allowing the strong to survive, accomplishes in its way an actual good becomes-clear. And the important biological lesson is also enforced, that there is a tolerably deep meed of philosophy involved in the Laureate's pertinent remark concerning the "secret meaning" of the deeds. of Nature, through