8 FEMALE BITTERLING I 



alcohol, however, used as solvent for a-tocopherol acetate, 

 disturbs the reaction in a concentration of 0.05 ml per 750 ml 

 v^ater. For this reason we thought that vitamin E must be 

 active in the ovipositor test (DUYVENE DE WiT, i 941 ). This, 

 however, proved to be incorrect (VAN KOERSVELD) . Vitamin 

 E, added in solution to the aquarium water, is inactive. We 

 have not yet tested its activity when injected; nor have we 

 investigated its influence upon, the fertility of fishes. 



Closer consideration of the reaction to members of the 

 estrane, pregnane, and androstane group shows that the 

 growth-curves obtained with these substances differ, which 

 again proves the specificity of the ovipositor test. This is illus- 

 trated in Fig. 3, where the growth-curves, obtained after ad- 



progesterone 



dehydroandrosierone 



estrone 



14 18 22 26 ^ 30 

 hours 



Fig. 3. Ovipositor growth-curves after the administration of progesterone, 



dehydro-androsterone and estrone. Note the typical differences between 



the respective curves. 



ministration of optimal quantities of progesterone, dehydro- 

 androsterone and estrone, respectively, are given. It will be 

 seen that progesterone shows a latent period of i hour; after 

 4^ hours the period of linear growth is ended. With dehy- 

 droandrosterone, the latent period is also i hour; but 5^2 

 hours after the commencement of the experiment, linear 

 growth increases in intensity. With estrone the latent period 

 is 5 3^ hours, after which a linear growth period sets in, up 

 to 60 hours after the commencement. 



Although these values are, in the absolute senses, subject 

 to seasonal fluctuations, their relative differences remain for 

 the greater part unchanged. 



On the basis of these differences it is possible to different- 

 iate between the representatives of the estrone, pregnane, and 



