There is no question that the artificial feeding of infants has taken remarkable strides in the past few years. It has had such success that in the minds of many physicians and perhaps a large proportion of the public there has grown up the idea that artificial formulas can safely replace breast milk without any detrimental results to the child. So far as we know, this has been based on empirical observations and has not been supported by sufficient evidence to be regarded as in any way proof. Although in the past few years many accessory foodstuffs have unquestionably been discovered, notably vitamins, which are necessary for life, and it has been discovered also that in many instances the inorganic materials were of far greater importance than had been suspected, one cannot be at all certain that all the elements which go to make up a perfect food have been