52 McCOLLUM— RELATION OF DIET TO PELLAGRA. 



in the preceding paragraph, has produced incipient pellagra experi- 

 mentally in man, but this claim has been disputed by other competent 

 observers. In our experimental work with the diet of peas, crackers 

 (wheat flour and fat), and cottonseed oil, which in the experience 

 of Chittenden and Underbill produced in dogs a condition resem- 

 bling pellagra in man, produced in rats only general malnutrition, 

 without the skin changes, diarrhea, or pathological changes in the 

 mucosa of the alimentary tract. Are we to accept the view that 

 pellagra is actually produced by a deficiency of something necessary 

 to the normal nutrition of man but not necessary for the rat ? The 

 possibility that the dogs of Chittenden and Underbill were infected 

 is not excluded, and an infectious agent may well have established 

 itself in animals restricted to a diet so faulty as one derived from 

 crackers (wheat flour and fat), peas, and cottonseed oil. Gold- 

 berger seems to have safeguarded his experimental men against in- 

 fection, and it is unfortunate that a sufficient number of undisputed 

 authorities were not called into consultation to forestall the possi- 

 bility of a question arising concerning the accuracy of the diagnosis 

 of pellagra, such as McNeal has raised. 



We are left in the situation which has arisen in the discussion of 

 the etiology of scurvy. It has been clearly shown that there is <no 

 difficulty in repeating the experimental work which demonstrated 

 that a guinea pig will develop severe scurvy (or some syndrome 

 resembling it) on a number of diets on which the rat will thrive 

 during the growing period. Does this mean that the guinea pig 

 requires one or more chemical complexes for its nutrition that are 

 dispensable to the rat? There is no doubt that the guinea pig nor- 

 mally takes a diet rich in succulent vegetables, and which produces 

 bulky, easily eliminable feces. The rat and swine, as well as man, 

 thrive on certain diets which leave little indigestible residue. Such 

 special requirements in the guinea pig make it next to impossible to 

 compare this species with man or the rat in similar dietary studies. 

 The experimental data obtained with the guinea pig must be used 

 with caution in reasoning concerning the etiology of human scurvy. 



In our attempts to produce in animals a condition analogous to 

 pellagra in man we have not been successful, but have observed only 

 a generalized poor condition instead. The evidence is practically 



