128 Discussion 



the chorioallantoic membrane, so what was weighed were the caruncles 

 and placentomes and not the placenta. 



There are two points; first, Dr. Fahmy and I gave a paper at the 

 Federation in Atlantic City last year (1954) in which we showed that 

 alkaline phosphatase and glycogen never appear in the same cells, but 

 when glycogen disappears alkaline phosphatase comes into the picture. 

 So that we might have a curve showing an uprise of alkaline phos- 

 phatase activity — we have not estimated that. 



Secondly, as the placenta gets thinner, then it is more efficient; 

 diffusion goes on. As far as one can see from the work being done, the 

 physio-chemical diffusion as such plays practically no part at all. It is 

 only between thinning and diffusion so that it is almost a facilitated, a 

 temporal cytological action involving energy consumption. 



Amoroso : If we agree that the placenta is a transient tissue, then the 

 structures, variously described as endometrial cups or craters and which 

 occur transiently in the placenta of the equidae, must be regarded as 

 transient tissues within a transient tissue. They have been fully 

 described and are figured in Brit. Med. Bull. (1955) vol. 11. 



