82 THE VITAMINS 



carbohydrate metabolism was made by Lepkovsky, Wood and Evans 

 (1930) through glucose tolerance tests conducted on carefully paired 

 rats on diets designed to differ only in their content of vitamin Bi. In 

 animals suffering from only slight deficiency in vitamin Bi the glucose 

 tolerance curves did not vary greatly from the controls, but in others 

 showing typical signs of beriberi there was evidence of definite inter- 

 ference in carbohydrate metabolism. 



Evans and Lepkovsky (1929) have presented evidence of the spar- 

 ing action of fat on antineuritic vitamin B, but not on the heat-stable 

 vitamin G, which function they show to be due to fat itself and not to 

 the presence of the vitamin as an impurity. 



Relation to Reproduction and Lactation. — One of the findings em- 

 phasized by McCarrison was the constant and pronounced atrophy of 

 the testes and similar but less marked atrophy of the ovaries among 

 animals which had been confined to diets lacking in vitamin B. The 

 atrophy of the male gonads was said to be much more pronounced in 

 pigeons than in monkeys. Funk and Douglas (1914) had previously 

 reported atrophy of the testicles, with shrunken tubules and absence of 

 spermatozoa in polyneuritic pigeons. Allen (1919) examined histologi- 

 cally the testes of rats which had been fed on Osborne and Mendel's 

 vitamin B-deficient diet and reported considerable but irregular degen- 

 eration, not all of the tubules being equally affected. Drummond 

 (1918) reported that male rats deprived of vitamin B for more than 

 14 days cease to breed with normally- fed females. For a more detailed 

 discussion of the effect of vitamin B deficiency on reproduction in 

 the male rat, see Parkes and Drummond (1925). While admitting that 

 degenerative changes may be initiated in the testes of pigeons by a wide 

 range of unfavorable conditions, Marrian and Parkes (1928) were of 

 the opinion that the testicular degeneration resulting from a deficiency 

 in vitamin B is not necessarily the result of inanition. Vitamin G, how- 

 ever, is considered by them to be less necessary than vitamin B for the 

 maintenance of nutrition of the testis. 



Findlay (1928) pointed out that the testicles of some rats deprived 

 of vitamin G showed spermatozoa while in all of those deprived of 

 vitamin B there was complete absence of spermatozoa. On the other 

 hand, Mattill (1927) and also Evans (1928b) hold that if vitamin E 

 is adequately provided, neither acute nor chronic deficiency of vitamin 

 B impairs the male germinal elements, although a decrease in sex in- 

 terest is observed. Evans and Bishop (1922b) found that ovulation is 

 affected more readily by lack of vitamin B than by the general con- 

 dition of the body. 



