148 CORTEX 



tion of the adrenal. Nor has the author been able to find an 

 appreciable supply of the cortical hormone in the corpora lutea 

 of pigs or cattle which might act as a store for the hormone. 



Firor and the author were unable to prolong the life of 

 adrenalectomized dogs by inducing in them pre-operatively an 

 artificial estrus by injection of theelin or the gonadotropic 

 substances of pregnancy urine or of the hypophysis. Appar- 

 ently such artificially induced estrus does not duplicate all 

 the physiological changes occurring in natural estrus as is also 

 indicated by other experimental work. 



Castration. Castration according to some authors prolongs 

 the survival of animals after adrenalectomy. One might an- 

 ticipate that the reduced metabolic activity of the castrated 

 animal would enable it to survive the extirpation of the adrenals 

 for a longer period as compared to the survival of the more 

 active normal animal. On the other hand, the increased 

 adrenal activity of the female in estrus, described in the pre- 

 ceding paragraph, would tend to prolong its survival beyond 

 that of a castrated female. The diversity of results obtained 

 by different authors as to the effect of castration on survival 

 after adrenalectomy may result from the extent to which the 

 factors just outlined have affected their results. 



Sex. Except for the effects of estrus and pregnancy, no 

 appreciable difference has been demonstrated between the 

 survival periods of male and female animals. In dogs Rogoff 

 and Stewart 628 found a mean survival of 7 days for 34 male dogs 

 as compared to 6| days for 39 non-pregnant females. The 

 observed difference is of no significance in view of the marked 

 variation of the individual results from the mean. Sisson and 

 March 577 report that female rats survive longer than males, 

 but their conclusion is based on the results obtained on only 

 11 animals. In a series of 100 consecutive operations on 

 immature rats selected at random from the data of Firor and 

 the author the average survival for male animals was 6.0 days 

 as compared to 6.1 days for the females. It is possible that the 



