THE HORMONES IN HUMAN REPRODUCTION 



of the gland and purify it ; but how are we to know when we 

 have it and how much we have? This question is answered by 

 our experiments on rabbits, just cited. All we need to do is to 

 mate a rabbit, remove the ovaries next day, and then admin- 

 ister our extract to see whether it will cause progestational 

 proliferation, and if so, how much extract is required. 



THE HORMONE OF THE CORPUS LUTEUM 



From this stage on I was fortunate indeed in having the 

 collaboration of Willard M. Allen, then a medical student^ 

 equipped with an excellent knowledge of organic chemistry. 

 We began, of course, in the dark. All we knew for certain was 

 that we had to extract something; we did not know what it 

 was or what its chemical properties might be. We had two 

 clues. In the first place, practically all the known important 

 chemical substances in the animal body can be dissolved and 

 therefore extracted by either water or alcohol, provided they 

 are protected from breaking down, spoiling, or being digested 

 in the process. (Incidentally, how can you protect a substance 

 from spoiling if you do not know what it is?) In the second 

 place, we had a hint from the work of Edmund Herrmann, 

 mentioned in Chapter IV, p. 82. Some of his photographs, 

 published in 1915 in the report of his work on the ovarian 

 hormone (i.e. estrogen) showed that without realizing it he 

 had produced progestational proliferation with some of his 

 extracts. From his report we knew that whatever he had in 

 his extracts must be soluble in alcohol. Willard Allen and I 

 began therefore by collecting corpora lutea of sows' ovaries 

 from the slaughterhouse. We minced them up in a meat chop- 

 per and extracted them with hot alcohol. Very luckily for us, 

 Walter R. Bloor, then professor of biochemistry at Rochester, 

 is a great expert on animal fats and allied substances. We 

 built our extractors from his design and sought his advice on 



2 Now Profepsor of Obstetrics and Gynecology, Washington University, 

 and head of the St, Louis Maternity Hospital. 



{ 112 } 



