ISOLATION OF SEXUAL HORMONES 325 



different chemical methods Herrmann obtained a thick yellow 

 oil which became solid when cooled. This substance showed 

 the characteristic reactions of cholesterine and contained 

 carbon, hydrogen and oxygen. According to Herrmann it is 

 possibly a derivate of cholesterine, soluble in alcohol, ether, 

 petrol-ether, acetone and benzol, but insoluble in water. 

 Herrmann examined the physiological effects of all the dif- 

 ferent fractions obtained in preparing the above-mentioned 

 oily substance. The experiments were made on fully grown 

 castrated rabbits and on young animals eight weeks old. 

 By injecting the extracts the atrophy of the uterus which 

 normally follows castration was inhibited, and the changes 

 characteristic of the normal "heat" took place in the uterus. 

 Very striking results were obtained on young animals {Fig. 123). 

 After three injections an extraordinary development of the 

 uterus began; there were changes in the mucosa and in the 

 muscle layer. The infantile uterus increased enormously, and 

 the blood vessels were very enlarged. There were glands in the 

 mucosa and the muscle layers were much more pronounced 

 after the fifth injection. The stroma of the mucosa now con- 

 sisted of cells very like decidua cells. Extraordinary changes 

 took place also in the vagina, in the tubes, and in the mammary 

 glands. The latter began to secrete, and a quantity of clear 

 fluid could be pressed out. These phenomena were observed 

 also with young animals previously castrated. Similar changes 

 in the mammary gland occurred with injected males. 



It is of great interest- that the ovary also is influenced by 

 the extract {Fig. 124). The ovary of the young rabbit 

 consists mainly of primary follicles {Fig. 124 A), but there are 

 also some follicles just entering upon development. In the 

 ovary of an animal which received five injections numerous 

 ripening follicles were to be found {Fig. 124 B), and some of 

 them had even already attained maturity. 



It follows from these experiments that the extract prepared 

 by Herrmann may cause in animals of about eight weeks a 

 development of the sex characters such as is found at an age 

 of about six to seven months. The genital organs may even 

 develop so far as to become like those during heat or at the 

 beginning of pregnancy. As far as I am aware, Herrmann 

 obtained all these changes by injecting preparations of the 

 corpus luteum and the placenta, but not by preparations of 



