A HORMONE FOR GESTATION 



suppressed the paper and telegraphed for Allen. We decided 

 that I needed a vacation and that we would look for the 

 trouble in the fall. In September I made another batch with 

 Allen watching every step, but not touching the apparatus. 

 It was no good. What could be wrong.'' Since my laboratory 

 was sunnier than his, perhaps my hormone was being spoiled 

 by sunlight. I had a room blacked out and made a batch in 

 the dark. That failed. Then we remembered that Allen, being 

 a better chemist than I, usually got his extracts freer of su- 

 perfluous grease and therefore had to mix them with corn oil 

 (Mazola) so that he could inject them. Mine were greasy 

 enough to inject without added oil. Perhaps the corn oil pro- 

 tected his hormones somehow while mine spoiled. We checked 

 that idea — another two weeks gone — and that was not the 

 answer. Then in desperation we made a batch together, side 

 by side and almost hand in hand, each watching the other. We 

 divided it into two lots and tested it separately — Allen's 

 worked ; mine did not ! Eureka, my trouble was in the testing, 

 not in the cookery. 



The explanation will seem so silly that I almost hesitate 

 to admit what it was. The fact is that rabbits do not respond 

 well to progesterone until they are about 8 weeks old and 

 weigh about 800 grams. We did not know this, and our rab- 

 bits ranged from 600 to 1,200 grams. When we went to the 

 cages to inject them, Willard Allen's idea of what constitutes 

 a nice rabbit led him to choose the larger ones, while I must 

 have had a subconscious preference for the infants. My ex- 

 tracts had been as good as his all the while, but my rabbits 

 were insensitive. It is staggering to think how often the success 

 or failure of research may hang upon such an unimaginable 

 contingency. 



We thought very hard about this experience, and decided 

 that after all we should not have expected that the hormone 

 of gestation would act upon an infant's uterus. Caring for 



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