Transplantation of Suprarenals 459 



age and the unhealthy individuals eliminated from the list as 

 was done for the daughters. Other factors recognized by us are 

 also involved ; but we know from much other work that although 

 there is a wide individual variation the normal age of maturity 

 for groups of these doves lies above 160 days. It is almost cer- 

 tain that the transplants did not retard the period of sexual ma- 

 turity in the females; and, if the extreme tameness which de- 

 veloped from the repeated handling of these birds could be 

 eliminated as a factor (which we can not now do) it would be 

 come highly probable that the repeated transplantations accel- 

 erated the attainment of sexual maturity in the females. 



The data of table 2 indicate that, as administered by us, 

 four injections of fresh suprarenal tissue of the ox into young 

 ring doves did not give results comparable with those from the 

 above transplantation tests. After these injections the growth 

 curve was normal or nearly normal for both males and females. 

 The three surviving males attained and maintained body weights 

 of 166-192 grams (ave., 177) ; the four females, 151-173 grams 

 (ave., 158). All of the four tested females matured perhaps 

 later than is normal, the earliest at 208 days and the group at 

 an average of 260 days. 



A water soluble extract of ox cortex is reported by van Her- 

 werden 1 to have shown favorable effects on health and growth 

 of Daphnia, Limnea and tadpoles. Our four injections of this 

 tissue into doves during a 10-day period would not adequately 

 test its effect on growth; but that such administration of ox 

 suprarenal does not produce the same- results on the age or time 

 of female sexual maturity as does transplantation of the supra- 

 renals of closely related individuals, is indicated by the data ob- 

 tained by us. Obviously there were differences in both the 

 source and the quantity of the tissue absorbed; and an extreme 

 difference in the rate of absorption of the injected and grafted 

 tissues. If, however, the transplanted tissue functioned during 

 several days it may have exercised much the greater action. 



lv. Herwerden, M. A., Biol. Zentralb., 1922, xlii, 109. 



