104 INFLUENCE OF HORMONES 



Gustav Born suggested, and Frankel tested the 

 suggestion experimentally, that the corpus luteum 

 of pregnancy is a gland of internal secretion whose 

 function is to cause the attachment of the ovum in 

 the uterus and the normal development of uterus 

 and placenta. Frankel found that removal of both 

 ovaries in rabbits between the first and sixth days 

 after fertilisation prevented pregnancy, and that the 

 same result followed if the corpora lutea were 

 merely destroyed in situ by galvano-cautery. Either 

 process carried out between the eighth and twentieth 

 days of pregnancy causes abortion. 



Lane-Claypon and Starling also found that re- 

 moval of both ovaries in the rabbit before the 

 fifteenth day was apt to cause abortion, but at a 

 later stage the same operation could be performed 

 without interfering with the course of pregnancy. 

 According to these authors numberless instances 

 prove that in women double ovariotomy does not 

 necessarily interfere with the course of pregnancy or 

 the development of the milk glands. Parturition 

 may take place and be followed by normal lactation. 

 This shows that a hormone from the corpora lutea is 

 not necessary either to the uterus or the milk glands, 

 at any rate in the last third of pregnancy, though 

 of course this does not prove that such a hormone is 

 not necessary for the earlier stages both of pregnancy 

 and growth of the milk glands. 



The results of Steinach, if confirmed, would prove 

 conclusively that the ovaries and testes produce 

 hormones which determine the development of all 

 the sexual characters, not merely physical but 

 psychical. He adopts the view that the interstitial 

 cells or gland are the source of the active hormone. 



