CHAPTER VI 

 THE (ESTRUS-PRODUCING HORMONE 



{a) HISTORY OF PREPARATION 



The history of the preparation of the oestrus-producing prin- 

 ciple of the ovary may be divided into three periods. The first, 

 beginning about 1912, comprises all the early work on the 

 extraction of the ovary. At this time workers were largely 

 concerned with the preparation of ovarian extracts which 

 would have some action on the reproductive organs, especi- 

 ally in the ovariectomized animal. The majority of the 

 preparations appear to have contained the oestrus-produc- 

 ing hormone, and the positive effects reported probably 

 depended upon its presence in the extracts. The second period 

 may be said to have begun with the work of Allen and Doisy, 

 who adopted a specific test for oestrus-producing activity and 

 elaborated an easy technique for the examination of results 

 in the live animal. The oestrous cornification of the vagina of 

 rats and mice, which can be detected by means of vaginal 

 smearing, made both these advances possible. The methods 

 of extraction used by Allen and Doisy and by their immediate 

 followers in this field were essentially the same as those of 

 earlier authors. The third period begins with the prepara- 

 tion of oestrus-producing extracts in a water-soluble or 

 pseudo-water-soluble form. Progress may thus be said to 

 have alternated between advance in the technique of testing 

 and advance in the methods of preparation. 



Early work on ovarian extracts. The first ovarian extracts 

 appear to have been designed to prevent the atrophy of the 

 uterus which follows double ovariectomy. Jentzer and Beutt- 

 ner (315) and later Bucura (109) were among the first to 

 attempt this experimentally, but their saline extracts were not 

 effective. In 1906, Marshall and Jolly (451) produced transient 



