THE DEVELOPMENT OP THE EMBRYO ITSELF. 121 



cy in woman. But this is not, in the human subject at least, 

 invariably the site of impregnation. After the ovum has been 

 set free, as above described, it is conveyed into the oviduct 

 (Fallopian tube), though exactly how is still a matter of dis- 

 pute : some holding that the current produced by the action 

 of the ciliated cells of the Fallopian tube suffices ; others that 

 the ovum is grasped by the fimbriated extremity of the tube as 

 part of a co-ordinated act. It is likely, as in so many other 

 instances, that both views are correct but partial; that is to 

 say, both these methods are employed. The columnar ciliated 

 cells, lining the oviduct, act so as to produce a current in the 

 direction of the uterus, thus assisting the ovum in its passage 

 toward its final resting place. 



(Estnim. — As a part of the general activity occurring at this 

 time, the uterus manifests certain changes, chiefly in its inter- 

 nal mucous lining, in which thickening and increased vascular- 



Fie. 132.— Diagram of the human nterus 

 just before menstruation. The shaded 

 portion represents the mucous mem- 

 brane (Hart and Barbour, after J. 

 Williams). 



Fig. 133.— Uterus after menstruation has 

 just ceased. The cavity of the body 

 of the uterus is supposed to have 

 been deprived of mucous membrane 

 (J. Williams). 



ity are prominent. A flow of blood from the uterus in the form 

 of a gentle oozing follows ; and as the superficial parts of the 

 mucous lining of the uterus undergo softening and fatty degen- 



