i64 INTERNAL SECRETIONS OF THE OVARY 



of implants or extracts on the immature animal, found that 

 three ovarian reactions were characteristic of this treatment. 



(a) In the majority of cases foUicles matured and ovulated, as 



found by Smith and Engle. 



(b) Other follicles, however, in the same ovary, became atretic 



and underwent luteinization without ovulation in a 

 manner corresponding essentially with that described 

 by Evans. 



(c) A small number of follicles in the same ovary would 



become cystic and appear as ' Blutpunkte' on the 

 surface of the ovary. 



Zondek considers these results to show that only one anterior 

 pituitary hormone is involved, and that the complete luteiniza- 

 tion caused by the sodium hydroxide extracts is due to the 

 injection of relatively large amounts, while the characteristic 

 ovulation effect of the suspensions results from the substance 

 being present in comparatively small amounts. Zondek's 

 aqueous extract of anterior pituitary can apparently produce 

 the three reactions he describes in any proportion, according to 

 the amounts administered. 



Evans and Long (i86) failed to produce oestrus in the im- 

 mature rat by the injection of the alkali preparation. This 

 would be expected, since Zondek and Aschheim (658) found 

 that the ovulation-stimulating principle is destroyed by alkali. 

 On the other hand, if there are two anterior pituitary sub- 

 stances affecting the ovary, the mixed ovulation and luteini- 

 zation obtained by Zondek and Aschheim might be due to the 

 presence of both substances in the implants. This would, how- 

 ever, apply equally to Smith and Engle's preparations. 



With the evidence available at present, it is difficult to decide 

 whether two different substances are concerned in these effects, 

 but basing a conclusion on Evans' results with alkali extracts, 

 and Zondek and Aschheim's observation that the ovulation - 

 producing substance is destroyed by alkali, it seems not im- 

 probable that two are concerned, as supposed by Bellerby (58). 

 There is little doubt that the problem will soon be cleared up by 

 administration of (a) the NaOH extracts in smaller amounts, 

 (b) the two types of preparation simultaneously. 



