STUDIES IN THE EXPEEIMEXTAL AXALYSIS OF SEX. 599 



or development of the egg. It is a remarkable fact that one 

 of the control birds (Xo. 3) laid a very large proportion 

 of eggs which developed abnormally, abnormalities of a 

 greater or less degree being observed in more th;in oO per 

 cent, of the eggs. Some of these abnormally developing 

 eggs were simply abnormal in having the chick not snfEciently 

 forward at the fourth day ol incubation with the area vascu- 

 losa rather bloodless, but others sliowed actual structural 

 abnormalities, in two cases double-headed or double-bodied 

 monsters being produced, in others the back being twisted 

 into a peculiar shape. I have recorded this fact, as it demon- 

 strates very clearly that the production of these abnormalities 

 must have been a fixed character in this hen and not an 

 accidental occitrrence. 



5. The Effect ox the Blood. 



The normal serum of the fowl has a very powerful agglu- 

 tinating effect upon the live spermatozoa of the cock. If a 

 small quantity of the spermatozoa from the vas deferens is 

 mixed with a small quantity of normal blood-serum, it is 

 observed that in a few moments the spermatozoa, instead of 

 being dispersed through the fluid, are agglutinated in clumps 

 and stringy masses. In the space of a quarter of an hour 

 most of the spermatozoa will be found to be motionless, and on 

 transferring them to saline they do not recover their mobility 

 but are shown to be irrecoverably damaged. If we perform 

 this experiment with a suspension of the testis extract used 

 in our experiments, the same agglutinating effect is observed 

 in test-tube experiments, but the agglutination does not pro- 

 ceed so rapidly even when the tubes are incubated at 37° C, 

 because the suspension does not consist only of spermatozoa 

 but very largely of fatty materials and cellular debris. The 

 agglutinating effect of the serum obtained from an injected 

 hen (No. 2) was tested twice against a stispension of sperma- 

 tozoa and of testis extract and the result couipared with 

 samples of normal serum. No increased agglutinating power 



