4. Fortpflanzungslehre. 283 



cytophors and spermatocytes. Monocystis was also unusually abundant. 

 Amoebocytes were conspicuous in the seminal vesicles; the w riter regards 

 these as having the function of destroying the bacteria, for in normal worras 

 bacteria may be found ingested in the amoebocytes even if scarce elsewhere. 



Doncaster (Cambridge). 



776) Goodale, H. D., Some Results of Castration in Ducks. 



(ßiol. Bull. 20,1. p. 35—66. 11 figs. Including five plates. 1910.) 



The paper deals almost wholly with the effect of castration on the secon- 

 dary sexual characters. A careful description is first given of the normal 

 plumage of the young and of males and females at the breeding time and in 

 summer. Seven males and five females were castrated; of these three males 

 and two females lived for considerable periods. Descriptions with figures 

 follow. 



"The results of these experiments show that removal of the testes does 

 not bring about the assumption of the female characters, but at most results 

 in the loss of a male character. The loss of the power of taking on the 

 summer plumage is similar to the loss of power by the castrated stag of 

 renewing the antlers each year. Whether castration of the drake, very early 

 in life, will prevent the assumption of the breeding plumage will be deter- 

 mined later." 



"Removal of the ovary, however, has an entirely different result. The 

 female after a time may gradually lose her normal characters and assume 

 those of the male. The results entirely confirm previous observations along 

 this line. Darwin records a duck which in old age assumed the perfect 

 winter and summer plumage of the drake. Korscheit also records a similar 

 case." 



"It is suggested that the female owes her color to the presence of some 

 modifying element, which prevents the development of the male color. It is 

 also suggested that the modifier may sometimes be responsible for sex limited 

 inheritance." 



"Cases in which the patency of sex has changed are pointed out. This 

 suggests that a common basis for the present contradictory evidences regard- 

 ing the determination of sex may be found in the hermaphroditic condition." 



Lillie (Chicago). 



777) Smith, Gr. (Oxford University), Studies in the Experimental 

 Analysis of Sex. V. On the effects of Testis-extract Injections 

 upon Fowls. 



(Quart. Journ. Micr. Sei. 56,3. p. 591—612. 1911.) 



Walker has recorded that injeetion of testis-extract into hens caused 

 an increase in the comb, which ceased when the testis injeetion was given up. 

 The author has repeated these experiments on a larger scale, and finds no 

 such result. In some cases the combs increased considerably, but equal or 

 even greater increase was found in the combs of some of the control birds. 

 The combs vary greatly from time to time, and he attributes Walker' s re- 

 sult to the accidental increase in the comb at the time of injeetion. The in- 

 jeetion had no constant effect on the health, fertility or weight of the birds. 

 The blood-serum has a marked agglutinating effect on the spermatozoa, and 

 this was not altered in the injeeted birds. Some of the injeeted birds laid 

 eggs which developed into normal chicks. One control bird (not injeeted) 

 constantly produced a large proportion of abnormal embryos in its eggs, but 

 no such result was observed in an injeeted bird. It is concluded that there 

 is no evidence that the testis contains an internal secretion which, injeeted 



20* 



