Another striking feature of the cibicultural age is the practice of bringing children up by hand. Among the pre-cibiculturists no infant can survive unless the mother can suckle it. Indeed, recognizing that if the mother dies during child-birth or if she cannot suckle her infant, it cannot be reared, they deliberately destroy it. Thus it came about that prior to cibiculture all mothers with defective nursing capacity were racially eliminated, i.e. prevented from leaving offspring who might inherit their defect, just as were those who were deficient in maternal instinct - in the love of, and willingness to sacrifice themselves for, their offspring. For this reason the mammary function and the maternal instinct were, and still are, kept at a high level of efficiency among the pre-cibiculturists. The like is true of the early agriculturists. Not until man learned to obtain the milk of certain animals he had domesticated, such as the goat, the mare, and above all the cow, was it possible for mothers defective in nursing capacity to rear their offspring; but these defective types being no longer racially eliminated, or at least not to the same extent as before, there has necessarily been taking place a lowering in the racial standard of mammary function. Similarly, when in the course of social evolution many mothers were able to relegate the care of their offspring to hirelings, it became easier for mothers defective in respect of the maternal instinct to leave behind them offspring all tending to inherit the like deficiency. It is not therefore surprising that in many respects the neo-woman should be maternally less well equipped than her primitive ancestors.
We may observe the same kind of process at work among domesticated animals. Their breeding instincts are found to have been warped by man's interference. For instance, under natural conditions only those hens which are good sitters could rear a brood of chickens, but man places the eggs of the bad sitters under good sitters, or he artificially incubates them in a "foster mother," and the bad sitters being thus enabled to have offspring, this type is becoming more and more common. The like is true of the artificially reared pheasant, which now rarely lays its complement of eggs in a single nest, but generally deposits them in several separate places.
Much as we may regret the fact, one can hardly doubt that women, whether from maternal incapacity or disinclination, will tend more and more to bring up their children by hand, and that the mammary function will in consequence undergo a progressive atrophy. Side by side with this maternal devolution we may look for a corresponding evolution to take place, by natural selection, in the digestive organs of the young human. Seeing that cow's milk has come to be the chief food on which artificially fed infants are reared, we may expect the infant's stomach to evolve the power of digesting this particular milk, and one cannot but wonder whether some enterprising person may not one day attempt the task of breeding an animal of which the milk shall approximate in composition to human milk, so that the two evolutions, digestive in the infant and mammary in the animal, shall proceed towards the same point and eventually meet.
On this subject it must suffice to observe that whereas the drink of pre-cibicultural man is almost entirely confined to natural water, neo-man relies almost entirely on artificially prepared beverages.