That for the nine months preceding its birth the infant obtains its nourishment directly from its mother's blood, and for nine months after birth it obtains this, normally, from her milk--_her_ digestive processes having so assimilated the originally brute and vegetable proteids of her food that these are now _human_ proteids, and are ready, therefore, to be built into the infant's body with the least possible tax upon its own assimilative powers--proves a number of important facts. First: that an infant's digestive powers remain, normally, for nine months after birth, in a more or less embryonic state; slowly and gradually developing capacity to convert the products of the brute and vegetable kingdoms into forms suitable for building into its human organisation. (Just as we see the digestive organs of the child progressively developing power to assimilate an adult dietary.) Secondly: that the infant's digestion remains thus undeveloped obviously in order that as little as possible of its vital power may be expended in the complex processes of assimilation, all available vital-power being urgently required for its exhaustingly rapid brain- and body-building. Thirdly: that where an artificial diet forces precocious development upon the infant-digestion--since all precocity is degeneracy, all the organs concerned in digestion will be, necessarily, more or less structurally defective and functionally inefficient; as a consequence of not having been permitted time and rest to develop slowly and stably over the normal allotted period. (Proof is supplied by the premature development of teeth, which occurs in artificially-fed babies some months before dentition is normally due. And these teeth and those that succeed them are of such perishable structure that present-day children need perpetual dental repairs.) Fourthly: that such misapplication of vital resources for the premature development and abnormal functions of precocious digestive organs entails inevitably corresponding loss of vital power for general development. Fifthly--and by no means lastly, but perhaps most important of all: that since the infant-digestion is quite incapable of properly converting brute and vegetable-proteids into human proteid, infants artificially fed must necessarily _build into their brains and bodies lower-grade proteids_--and proteids so imperfectly assimilated as to be something less than human, and, accordingly, more or less brute or vegetable still in their inherences. And since all living cells and tissues reproduce upon the plan of the parent-cells and tissues they were derived from, it is clear that the abnormal cells and tissues constructed of these half-brute, or half-vegetable proteids must be abnormal; unstable and degenerate, and prone to lapse readily to still further degrees of deterioration and disease.