EFFECTS OF INANITION ON THE BODY AS A WHOLE III 



vitamin B (" antineuritic ") ; and the antiscorbutic "water-soluble C " or vitamin 

 C. A fifth, or "vitamin X," has recently been discovered by Evans. 



The chemical nature and the exact physiological functions of the vitamins 

 are still uncertain. Hopkins concluded that they are catalytic, stimulative 

 . agents, possibly affecting both external and internal secretions. Similar views 

 have been advanced by various workers. Chick ('20) emphasizes the greater 

 need for vitamins when metabolism is accelerated (by work, low temperature, 

 growth, pregnancy, lactation, etc.), which is very suggestive. McCarrison 

 ('21) believes that in the absence or inadequacy of vitamins, there results a 

 disturbance of metabolism, so that the other dietary constituents cannot be 

 properly utilized in the various organs. Abderhalden ('22) concludes that the 

 vitamins promote the oxidative processes in the cells of the body. 



As many investigators have observed, there are marked differences among 

 species as to the effects of vitamin deficiency, which will be mentioned later. 

 Thus Hess ('22) states that: 



"In relation to the antiscorbutic vitamin, man reacts as does the guinea 

 pig; in respect to vitamin B, he reacts like the pigeon or fowl; and in respect 

 to vitamin A (fat soluble factor), he resembles the rat. The rabbit, for reasons 

 entirely unexplained, withstands deprivation of any vitamin with comparative 

 impunity, and therefore is not employed in any biologic test for these factors. 

 Furthermore, a diet which leads to a definite avitaminosis in one animal, leads 

 to a quite different one in another animal. For example, a diet of polished rice 

 brings about polyneuritis in the fowl or in the pigeon or in the rat, but induces 

 scurvy in the guinea pig." Sugiura and Benedict ('23) have raised pigeons 

 from hatching to maturity on diets deficient in both vitamins A and C. 



The effects of vitamin deficiency upon the various individual organs of the 

 body will be considered in the appropriate later chapters, but some more general 

 effects upon the body as a whole may now be considered. 



McCollum and Simmonds ('17, '18) observed that, since vitamins (A and B) 

 are not synthesized in the body, they must be present in the diet or (after exhaus- 

 tion of the amounts previously stored in the body) they will be absent from the 

 milk of nursing rats, with consequent failure of growth in the young. It seems 

 inappropriate to speak of any single "growth vitamin," since all appear (in 

 most species) to be necessary for optimum growth. Funk, however, claims that 

 the growth-promoting factor in vitamin B may be separated as a distinct 

 "vitamin D" (cf. Funk and Paton, '22). Evans and Bishop ('22a, '23a, '23b) 

 distinguish a "fertility conferring factor X," in the absence of which the pla- 

 centae of rats are abnormal and the embryos invariably resorbed. 



Vitamin A. — We have previously noted that the earlier failures to obtain 

 growth upon diets free from fats and lipoids were probably due chiefly to the 

 elimination of the closely associated "fat-soluble A" (cf. Stepp '22). The 

 term was introduced by McCollum and Davis ('15, '17), who had previously 

 ('13, '14) noted failure of continued growth in rats upon diets free from this 

 factor. Osborne and Mendel ('13, '17a, '21) and Hess, McCann and Pappen- 

 heimer ('21) obtained similar results in rats, and Mackay ('21) likewise found 

 that kittens on a diet deficient in vitamin A cease growth and become emaciated. 



