32 FEMALE BITTERLING I 



Standard cycle of 28 days. It is evident from this figure that 

 the secretion of pregnanediol, representing the secretory 

 activity of the corpus luteum, increases linearly from the time 

 of ovulation until the seventh day of life of the corpus 

 luteum. After this, secretion diminishes, gradually at first, 

 then more quickly, ceasing entirely on the first day of the 

 next menstruation. 



With regard to the crosses representing the hormone con- 

 tent of the corpora lutea examined, it appears that they are 

 placed in a zone whose form is about the same as that of the 

 secretion-curve referred to above. 



During the first 7 days after ovulation, i.e., during the 

 growth of the corpus luteum, it appears that there exists a 

 distinct parallelism between secretory activity and progester- 

 one-content of the corpora lutea. During the 7 days follow- 

 ing, i.e., during the degeneration of the corpus luteum, it 

 appears that the secretory activity diminishes faster than the 

 hormone content. 



This phenomenon no doubt results from the fact that, 

 during the decreased production of hormone, the corpora 

 lutea still retain their normal stock of hormone for some 

 time, until degeneration of the tissue has proceeded far 

 enough for the hormone to disappear. One has the impression 

 that the decrease in hormone content sets in about 4 days 

 later than the decrease in hormone production. (Vide the 

 dotted line in Fig. 36, shifted 4 days to the right). 



The hormone contents found suggest that further inves- 

 tigations should be made into the question of whether the 

 substance present in the corpora lutea and active in the ovi- 

 positor test should be attributed either wholly of partly to 

 progesterone. In the latter case the reactions found should 

 be the sum of the reaction to progesterone and those to the 

 remaining active agents. The ovipositor test should then, 

 generally speaking yield higher values than is consistent with 

 the amount of progesterone present in corpora lutea. In the 

 ovipositor test, reactions are obtained, per gram of tissue of 

 mature human corpora lutea, which correspond to tliose of 

 10 — 20 7 progesterone. Clauberg (1932), in his experi- 



