444 MAMMALIA— PHYSIOLOGY 



of the placenta, and perhaps related to the metabolism of iron. It 

 is not affected by ordinary temperatures. 



The writer holds that resorption of the young in female rats on a 

 Vitamin E deficient diet is really an iodin effect, comparable to that 

 induced in a shorter period of time by excess iodin. Wheat germ 

 and hemp seed oils that are so effective in the treatment of Vitamin 

 E deficiency are rich in the highly unsaturated fatty acids during 

 their effective period. The effectiveness of these oils is lessened as 

 the period of germination advances and the oils become more 

 saturated. (See page 437.) 



What Are Vitamins? — The author holds that the " vitamins " 

 are really proper combinations of minute quantities of chemicals 

 that are functional as catalyzers, and make available not only the 

 proteins, carbohydrates and fats that are in combination with them 

 in food-stuffs, but that they also furnish the proper medium for the 

 liberation of food-stuffs stored in the organism. The influence of 

 these potent chemicals is felt in all glandular function, and particu- 

 larly of course in the activation of the endocrine glands. 



The Organs of Internal Secretion. Endosecretory Glands with 

 a Duct. Testis. — In addition to sperms, an external secretion, the 

 testes furnish an internal secretion responsible for the male secondary 

 sex characters. Steinach found that transplantation of the testes 

 into spayed female guinea pigs induced masculinization. Lydston 

 and others have transplanted human testes, with temporary benefit.^ 



Ovary. — The ovary produces eggs and regulates the female 

 secondary sex characters. In the fowl Goodale found that removal 

 of the ovary causes the bird to take on male plumage. Domm found 

 that a compensatory testis-like structure developed on the right side. 

 Steinach found that castrated male guinea pigs could be feminized, 

 by implanting ovaries in their body cavities. 



In early or normal menopause, and in epilepsy, ovarian extracts, 

 notably corpus luteum and folliculin extract, are beneficial. Allen 

 and Doisy have cured some cases of sterility with follicular liquid. 



Liver. — The liver secretes bile externally, and produces glycogen^ 

 a " negative internal secretion " which is an important body food, 

 and transforms harmful ammonia into harmless urea. A hormone 

 extracted from liver has been most successful in the treatment of 

 pernicious anemia. 



^ Consult Moore, C. R. 1926. Qu. Rev. of Biol., vol. i, pp. 4-50. 



