McCOLLUM— RELATION OF DIET TO PELLAGRA. 53 



nil that Chittenden and Underhill's dogs suffered all the pathological 

 changes which they record solely as the result of chemical faults in 

 the diet. Our experiments with their diet show it to be incapable 

 of maintaining satisfactory nutrition because of faults in the dietary 

 factors. The possibility of an infection in their animals is not ex- 

 cluded, and is indeed rendered probable if we grant that lowered 

 vitality predisposes to infection. These reasons together with the 

 lack of positive proof that the men restricted in Goldberger's experi- 

 ments to a diet similar to that described were actually developing 

 pellagra, warrant, we believe, our accepting as probably correct the 

 conclusions of the Thompson-McFadden Commission and of Jobling 

 and Peterson that pellagra is caused by an infectious agent, and 

 that unless it has been introduced into a district there -may develop 

 such a condition of lowered vitality from faulty diet or other debili- 

 tating influence as would predispose one to an attack, without the 

 appearance of the disease. The debilitating effects on animals of 

 diets derived from cereals, tubers, roots, and any food products 

 formed from the milling of grains together with legume seeds and 

 meats, are so striking that we believe similar diets would produce 

 in man a susceptibility to infectious diseases such as tuberculosis or 

 pellagra. We have come to hold the view, as the result of our 

 studies of diets of the type common in pellagrous households, that 

 the predisposing influence for both is in general the same, and the 

 character of the unsanitary conditions surrounding the individual 

 may determine which of these two diseases he will develop. 



From the studies which we have described elsewhere we are 

 enabled to point out definitely the relative values of several foods as 

 correctives in the diet of the pellagrous. Hitherto the legume seeds 

 and lean meat were classed with milk and eggs in this respect, and 

 nothing was said about the unique qualities of the leafy vegetables 

 as supplements for food mixtures derived from plant products of 

 the storage organ group. It is clear that the most important food 

 to be recommended for consumption in pellagrous districts is milk, 

 because of its cheapness as compared with the same protective value 

 in foods from other sources and its threefold corrective character 

 as contrasted with meat which enhances the type of diet found in 

 the pellagrous household only with respect to the protein factor, and 



