912 E. V. McCOLLTJM 



the theory that pellagra is caused by the consumption of maize. This 

 theory was revived by Lombroso, but numerous cases of the disease have 

 been observed in persons who have never consumed any maize. Fur- 

 thermore, in regions where some ate maize (corn) and others little or 

 none, the incidence of the disease has never been found greater among 

 the maize eaters than among those who make no use of this grain. Fur- 

 thermore, the view that certain toxic substances, formed through the action 

 of molds or other microorganisms growing in spoiled corn, are responsible 

 for the symptoms of pellagra, find no support in investigations of the last 

 decade. 



The researches of Kossel, Fischer and Osborne on the chemistry of the 

 proteins revealed the fact that certain proteins are lacking relatively or 

 absolutely in certain of the amino-acids which are essential for normal 

 nutrition. Other proteins are so constituted as to yield the indispensable 

 amino-acids in proportions very different from the optimal for trans- 

 formation into body tissues, and these are, therefore, proteins of low 

 biological value. Since zein, the principal proteili of the maize kernel, is. 

 entirely lacking in tryptophane, one of the digestion products of proteins, 

 it was suggested by Sandwith that pellagra might be explained by the lack 

 of this ammo-acid. Other investigators, especially Voegtlin, and Gold- 

 berger have reported results of studies with certain diets in pellagrous 

 districts and with others which proved effective for the cure of the dis- 

 ease, which are in harmony with the view that pellagra is induced by a 

 lack of certain amino-acids in the diet. It is not yet proven that this is the 

 true explanation of the cause of the disease, however, and indeed Voegtlin 

 has recently published experimental data which, if substantiated, will 

 serve as conclusive proof that pellagra is due to deficiency of a substance 

 or substances which should be classed with the vitamins. 



Voegtlin has recently reported experiments on pellagrins in which the 

 alcoholic extracts of fat-free liver or thymus were administered to patients 

 who were maintained upon a diet which had been shown not to cause any 

 improvement in patients suffering from the disease, or even to prevent 

 them from gradually getting worse. The administration of the extractive 

 material from these glands is reported to have given results comparable in 

 every way to those seen when patients suffering from "uncomplicated pel- 

 lagra" are given a diet containing liberal amounts of milk, eggs, meats 

 and fresh vegetables. 



There are some remarkable features about this report which are well 

 worthy of further observations. In the first place, alcohol is not an effective 

 solvent for amino-acids nor inorganic salts, so that the preparations given 

 the patients could not be regarded as of a nature suitable for the enhance- 

 ment of the protein moiety or the inorganic moiety of the diet, both of 

 which in the typical "pellagrous" diet are deficient and of poor quality. 

 In the second place, it seems remarkable that improvement so pronounced 



