VITAMIN B (Bi) 25 



ished rice was heated in an autoclave for two hours at 125° C, but 

 only partially destroyed when the temperature of heating was 115° C. 

 Similar results were obtained in experiments with other grains. Eijk- 

 man also showed that fowls rendered polyneuritic by feeding with 

 grain which had been heated in the autoclave could be cured by giving 

 water extracts of raw grain but not by phosphorus compounds prepared 

 from such extracts — a result of considerable importance at that date 

 since under the teaching of Schaumann there was a tendency to ascribe 

 the antineuritic property to some organic phosphorus compound. As 

 further evidence on this point Eijkman showed in 1911 that an extract 

 of rice polishings containing only the slightest traces of phosphorus 

 yet had marked curative effects in polyneuritis. He also showed that 

 the curative substances could be administered either by mouth or by 

 injection. 



Simultaneous with much of this work by Eijkman were the experi- 

 ments of Hopkins (1906, 1912) and those of Osborne and Mendel 

 (1911). The former showed that milk and some at least of the vege- 

 tables contained an organic substance or substances soluble in water 

 and alcohol which induced growth in young animals fed upon mixtures 

 of purified foodstuffs whereas when these foodstuffs were well purified 

 and fed without accessory substances growth always failed. Osborne 

 and Mendel further showed that the water solution remaining after 

 removal of fat, casein and lactalbumin from milk (the so-called protein- 

 free milk) was much more efficient in inducing growth than was a 

 corresponding mixture of lactose and pure salts or milk ash, thus 

 implying the presence of some water-soluble organic growth-promoting 

 substance. 



It was, however, principally in connection with the study of beriberi 

 and experimental polyneuritis in birds that the vitamin conception 

 was actively developed at the beginning of the second decade of this 

 century. Takaki's conquest of beriberi in the Japanese navy by a change 

 of ration did not carry conviction to many at the time because the only 

 explanation which he had to offer, namely, that the new ration was 

 richer in protein than the old, was seen to be inadequate ; and the work 

 of Eijkman and of Grijns did not at first command much attention 

 because many were slow to accept the view that the experimental poly- 

 neuritis of fowls was the same disease as human beriberi. Between 

 1900 and 1910, however, there was accumulated indubitable evidence in 

 support of the view that beriberi is essentially a nutritional disease 

 which may be prevented by the consumption of adequate amounts of 

 any of the foods containing the unknown antineuritic substance. 



