384: GENERATION. 



like the so-called cancer-cells. There has been and is now con 

 siderable difference of opinion with regard to the formation 

 of the decidua serotina. Some writers, who do not admit 

 that the placenta has any true maternal portion, regard it as 

 the portion of decidua imprisoned between the chorioii and 

 the muscular walls of the uterus ; l but, if we adopt the view 

 that the placenta is formed in part of the uterine mucous 

 membrane, we must regard the serotina, so called, as simply 

 the deeper portion of this membrane. 



Adopting the view, as we have, that the villi of the cho- 

 rion are bathed in the maternal blood in the substance of the 

 placenta, and that these villi originally penetrate the uterine 

 tubules, the theory lately advanced by Ercolani, that the pla- 

 centa contains utricular glands which elaborate a fluid for 

 foetal nutrition, from a theoretical point of view at least, is 

 not necessary to explain the nutritive functions of the pla- 

 centa. There is no reason to believe that there is any such 

 process of secretion in the placenta ; and it is more consistent 

 to assume that there is a simple transudation of nutritive 

 material from the blood of the mother through the vessels of 

 the foetal tufts. This opinion is not opposed to the demon- 

 stration, by Ercolani, of utricular glands, developed either 

 from the original uterine tubules or of new formation ; it 

 simply does not admit the function ascribed to these glands 

 by Ercolani, which rests upon purely theoretical considera- 

 tions. 2 



Blood-vessels of the Placenta. The two arteries of the 

 umbilical cord branch upon the foetal surface of the placenta 

 beneath the amnion, and finally penetrate the substance of 

 the organ. The branches of the veins, which are about six- 



T ROBIN, Memoire sur quelques points de Tanatomie et de la physiologic de la 

 muqueuse et de V epithelium uterins pendant la grossesse. Journal de la physiolo- 

 gic, Paris, 1858, tome i., p. 50. 



3 ERCOLANI, Memoire sur les glandes utriculaires de Vuterus et sur Torgane 

 glandulaire de nouvelle formation. Journal de V anatomic, Paris, 1868, tome v., 

 p. 501, et seq. 



