I do not mean that the adult Martians are unnecessarily or
intentionally cruel to the young, but theirs is a hard and pitiless
struggle for existence upon a dying planet, the natural resources of
which have dwindled to a point where the support of each additional
life means an added tax upon the community into which it is thrown.

By careful selection they rear only the hardiest specimens of each
species, and with almost supernatural foresight they regulate the
birth rate to merely offset the loss by death.

Each adult Martian female brings forth about thirteen eggs each
year, and those which meet the size, weight, and specific gravity
tests are hidden in the recesses of some subterranean vault where
the temperature is too low for incubation. Every year these eggs
are carefully examined by a council of twenty chieftains, and all
but about one hundred of the most perfect are destroyed out of each
yearly supply. At the end of five years about five hundred almost
perfect eggs have been chosen from the thousands brought forth.
These are then placed in the almost air-tight incubators to be
hatched by the sun's rays after a period of another five years. The
hatching which we had witnessed today was a fairly representative
event of its kind, all but about one per cent of the eggs hatching
in two days. If the remaining eggs ever hatched we knew nothing of
the fate of the little Martians. They were not wanted, as their
offspring might inherit and transmit the tendency to prolonged
incubation, and thus upset the system which has maintained for ages
and which permits the adult Martians to figure the proper time for
return to the incubators, almost to an hour.