Arti-ficial Parthenogetiesis in Thalassema Mellita 1 09 



V OBSERVATIONS ON THE LIVING MATERIAL 

 I The Unsegmented Egg 



In normal fertilization the spermatozoon enters the oocyte and 

 lies more or less quiescent in the cytoplasm during the changes 

 involved in the process of maturation which are initiated very 

 shortly after the appearance of the sperm inside the egg. Almost 

 immediately the egg throw^s off the membrane which soon draws 

 away from the surface and becomes completely detached, while 

 at the same time it becomes spherical, probably as a result of 

 the absorption of water. In the parthenogenetic eggs, the same 

 changes take place. After exposure to the acid solutions, the 

 eggs were in all cases transferred at once to sterilized sea-water, 

 when a typical fertilization membrane became apparent in a very 

 short time. The eggs do not round out as quickly, however, as 

 they do after the entrance of the sperm, but usually in about 30 

 minutes from the time they are placed in normal sea-water they 

 assume the spherical form, although it occasionally happens that 

 this change is considerably delayed and an hour or more may 

 elapse before they recover from the flattened, compressed con- 

 dition in which they are when taken from the tubes of the female. 



After treatment with the acid and transference .to sea-water, the 

 membrane formation was of absolutely universal occurrence and 

 was exhibited by every egg, whether sojourn in the acidulated 

 water wiis of the proper duration to produce subsequent cleavage 

 and development, or not. 



The eggs of my experiments exhibited the phenomena which 

 simulate the appearance of "spinning" activities and which have 

 been described by Torrey ('03) in the normally fertilized eggs 

 of Thalassema. If the perivitelline space be examined under a 

 high power, shortly after the appearance of the membrane, 

 excessively fine protoplasmic threads maybe seen passing from the 

 surface of the egg to the membrane and varying from time to time 

 in thickness and constitution. These delicate strands persist 

 during the cleavage stages, while some appear to be attached to 

 the polar bodies and give the impression of holding them in place, 

 as Torrey has described. The connections with the polar bodies, 



