MISCELLANEOUS WATER-SOLUBLE GROWTH FACTORS 



vitamin Bg deficiency was not affected by the caseinogen and was only 

 cured by the addition of an extract prepared from wheat germ. As 

 the result of subsequent work carried out jointly, C. W. Carter and 

 J. R. O'Brien ' reached the conclusion that caseinogen only fully 

 restored the weight of pigeons under certain special conditions, and 

 that vitamin B3 was needed in addition. They described the prepara- 

 tion of a concentrate from liver and attempts to purify the factor. 

 They found that most of the activity was adsorbed on fuller's earth. 

 Their results appeared to substantiate the earlier claims for the 

 existence of vitamin B5. 



Unfortunately, neither vitamin B3 nor vitamin Bg has ever been 

 isolated in the pure state, and it is therefore impossible to decide 

 whether they ought to be recognised as distinctive factors or not. 

 In the light of more recent work, which has indicated the large 

 number of water-soluble factors that are required by the chick (page 

 613), and presumably by pigeons also, it is reasonable to suppose that 

 the concentrates of vitamins Bg and Bg, which the Oxford workers 

 used, owed their activity to the presence of these other factors. J. G. 

 Lee and A. G. Hogan,^ for instance, concluded that vitamins Bg and 

 Bg were multiple in nature, the former being a source of pantothenic 

 acid and the latter of pyridoxine, but doubtless choline, bio tin, folic 

 acid and vitamin B^g also contributed to the effects produced. 



Vitamin B4 



Vitamin B4 is the name given to a heat-labile factor claimed by 

 V. Reader ® to be necessary for rats when maintained on a diet of 

 autoclaved cereals. In the absence of vitamin B4 the rats not only 

 ceased to grow but developed a hunched back, protruding jowls and a 

 wobbly gait. Administration of a vitamin B^ concentrate brought 

 about a gradual recovery which was believed to be due to the relief 

 of anorexia and a corresponding increase in the vitamin B4 intake. ^^ 



Kline et al}^ produced a vitamin B4 deficiency in rats by using 

 purified caseinogen and dextrin, crystalline vitamin B^ and a highly 

 purified concentrate of " vitamin B^". The deficiency symptoms 

 were relieved by feeding peanuts, which were assumed to be rich in 

 vitamin B4. Subsequently they observed ^^ that brain, kidney and 

 liver tissue also relieved the symptoms. 



Subsequent workers failed to confirm the existence of vitamin B4 

 and according to R. L. Swank and O. A. Bessey,^^ for example, a 

 deficiency of vitamin B^ would account for the paralysis in deficient 

 rats making it unnecessary to postulate the existence of vitamin B4, 

 whilst Briggs et al.}* using a diet with which they had previously 

 produced vitamin B4 deficiency in rats, found that the typical paralysis 



612 



