J 



22 Vitamines and Deficiency Diseases [June-September 



be investigated by comparing two pigeons, one f ed on polished rice and 

 the other on a normal diet. A similar experiment was performed 

 by Morpurgo and Satta (40), who kept two mice in parabiosis for 

 long periods, one of which was fed sucrose alone, the other a normal 

 diet. The former received vitamine and other necessary constitu- 

 ents from the general blood-supply. I have shown (35) that 

 pigeons, during attacks of beriberi, are able to utilize only a part 

 of their bodily stock of vitamine — the part contained in the less 

 vital tissues, e. g., muscle. Beriberi-pigeons lose about 25-40 per- 

 cent of their body-weight; but, if such a pigeon is extracted with 

 alcohol and the evaporated alcoholic extract given per os to another 

 beriberi-pigeon, the latter quickly recovers. No toxic effect of these 

 extracts was observed. 



Beriberi and glands of internal secretion. The products 

 of glands of internal secretion show, in their chemical character, a 

 certain degree of resemblance to vitamines. Vitamines might be the 

 precursors of these substances. It is too early to attack this problem 

 chemically, but Douglas and I (41) compared the pathological 

 changes produced in this relation in beriberi pigeons. We examined 

 pituitary, thyroid, suprarenals, ovary, testes, kidney, liver, pancreas 

 and Spleen. The glands examined .were diminished in size in every 

 case; microscopicaliy there were marked degenerative changes in 

 the most important cells, only the framework remaining. The most 

 marked change was the entire disappearance of the thymus, a 

 Symptom which must be regarded, however, as due more likely to 

 inanition than to beriberi. I found later, however, that the thymus 

 appears very quickly when vitamine is administered. 



Douglas (42), at my suggestion and by using the animals from 

 my feeding experiments, investigated the pathological changes in 

 thyroid under the influence of various diets, particularly of diets of 

 polished rice. No special changes were found, but it was observed 

 that the colloid of the vesicles had a tendency to disappear. The 

 most interesting glands of internal secretion that remain to be 

 investigated are the parathyroids, the removal of which induces 

 Symptoms somewhat similar to those of beriberi. 



