Subminimal provision of the uncharacterized nutrient principles, resulting in marked impairment of the neuro-muscular control of the intestine with consequent failure of the latter to transport its contents in a normal manner, the impairment of the assimilative, secretory and protective functions, McCarrison suggests as etiological factors in certain pathological states in human subjects which appear to be the counterparts of these experimentally induced states in animals. His views on this subject are very instructive.

Pigeons fed exclusively on a diet of polished rice frequently suffer from diarrhea, and this can be regarded as a symptom of vitamin deficiency, since it can in many cases be caused to disappear at once by the administration of alcoholic extracts of egg yolks. Diarrhea or colitis is almost a constant precursor or concomitant of "war edema," which, as has already been shown, is in all probability, due to the combined deficiency in the diet of protein and anti-neuritic substance. At least this fact is true in the wet form of beri-beri. Continued subminimal dietetic deficiency of certain sorts may lead to a state of chronic gastro-intestinal catarrh, which characterizes those conditions in which mucus in abnormal amounts is produced by the intestine. Mucous disease is very common among European children in India who are fed largely sterilized milk, artificial foods, white bread, polished rice, poor butter, over-cooked vegetables and excessive quantities of sugar. Therapeutic experience has shown that this malady yields to a rationally selected dietary. The mucous stools, the diarrhea, the marked irritability, the unhealthy appetite rapidly disappear on such a regimen, as do also the "night terrors" from which such children frequently suffer (McCarrison).

In the category of syndromes caused by protracted feeding children on insufficient diets, McCarrison also ventures to suggest "celiac disease," described by Still (21). It is thus characterized: "Absent in breast-fed children, its onset between the age of nine months and two years, the diarrhea which so frequently precedes it, the cessation of growth, the ill-formed, pale, 'oat-meal stools,' the frequent association of scorbutic symptoms, the abdominal distention, the afebrile nature of the malady, the diminished size of the liver, the blood changes, the occurrence of edema, the thin bones, the muscular feebleness - all these find their counterpart in pigeons fed on an exclusive dietary of auto-claved milled rice."

Again, McCarrison draws a parallel between the conditions observed in animals restricted to faulty diets of the types employed in his experiments and the anatomical factors seen in chronic intestinal stasis. Keith (22) regards defective action on the part of the abdominal musculature, and a lesion of the neuro-muscular system of the intestine, as the two factors of primary importance in the causation of this condition. Defective diet is certainly one means by which both the abdominal musculature and the neuro-muscular system of the intestine may be simultaneously impaired in functional capacity.

It must be kept in mind that McCarrison is hardly justified in speaking so unqualifiedly of "vitaminic deficiency" as the cause of the lesions observed. The extensive studies of McCollum and Simmonds and their co-workers have clearly shown the serious consequences of deprivation of certain of the essential mineral elements, notably calcium and phosphorus. McCarri-son's diets were almost without exception, greatly deficient in several inorganic elements, including calcium, phosphorus, sodium and chlorin, and apparently contained a decided excess of acid over basic radicals. Deprivation of chlorin quickly leads to inability of the stomach to secrete hydrochloric acid, and this alone would seriously interfere with digestion, and with the suppression of bacterial growth in the alimentary tract. Diets deficient in mineral salts to the extent true of a diet of polished rice, of rice and butter, or of rice, butter and onion, might well lead to a state of depletion of the alkali reserve in the blood. Such deficient diets may account for the air hunger which he attributed to acidosis brought about by acid of fermentation resulting from a diet too largely derived from carbohydrate. It is scarcely safe to attribute all the observed symptoms in his experimental animals to deficiency of the uncharacterized dietary essentials. The conditions which he described are, however, induced by dietaries of a type which is at the present time exceedingly common in Europe and America. Putting aside minor details which may require revision, the conclusions of McCarrison represent an important advance in our understanding of the relation between faulty nutrition of a certain type and physical deterioration.