452 VEDDER AND CLARK. 



Strong and Crowell(24) prove beyond the shadow of a doubt that 

 beriberi in man is the result of a too nearly exclusive diet of 

 polished rice, or of other foods lacking in the neuritis-preventing 

 substance. It has been proved beyond question that polyneuritis 

 of fowls is due to a similar diet. The cause of the two diseases is 

 therefore the same. Therefore, the conclusion already published 

 by Chamberlain and Vedder(6) "that the two conditions are 

 due to the same pathological process causing slightly different 

 manifestations in diverse species" is abundantly justified. Since 

 this is the case, it is evident that we may deduce some important 

 facts concerning the relation between diet and beriberi from the 

 above feeding experiments on fowls. 



Both meat and potatoes contain a certain, but relatively small, 

 amount of the neuritis-preventing substance. This explains the 

 immunity from beriberi of those races whose main articles of 

 diet are meat and potatoes. On the other hand, the man who 

 eats a pound of polished rice daily with a small or occasional 

 addition of meat will not receive complete protection from beri- 

 beri, although the onset of the disease may be delayed by the meat 

 thus eaten. Eijkman showed that fowls fed entirely on potato 

 starch did not develop polyneuritis. This confirms our observa- 

 tion that potatoes contain the neuritis-preventing substance. 

 If men live chiefly on potatoes, as many Irish peasants have 

 often done, they will be protected from beriberi, but a diet of 

 polished rice with a small addition of potatoes would result in the 

 production of beriberi. 



Our observation that ordinary white bread is quite lacking 

 in the neuritis-preventing substance is also interesting. This 

 confirms the observation of Hoist (25) that animals fed on wheat 

 bread developed neuritis while those fed on rye bread did not. 

 Beriberi began to appear on Norwegian sailing ships in 1894, 

 when the diet of the sailors was changed. Prior to that date they 

 ate largely rye bread. Subsequently they received wheat bread 

 and developed beriberi. The occurrence of ship beriberi among 

 sailors who live chiefly on bread or hardtack made of white or 

 overmilled wheat flour is thus explained. 



Little (26) has also recently reported the occurrence of beriberi 

 in Labrador and Newfoundland among a native population living 

 during certain seasons almost exclusively on white wheat flour. 

 This has been taken in some quarters as throwing doubt upon 

 the theory that beriberi is produced by a diet of polished rice. 

 However, since polished rice only produces beriberi because of 

 its deficiency in the neuritis-preventing substance and since 



