FCETAL NUTRITION: THE PLACENTA 405 



also been described in the trophoblast of the rabbit by 

 Beneden, and in the uterine mucosa by Schmidt, 1 who stated 



&* 



*<il/& i 



FIG. 93. First stage of cellular secretion in the placenta of the cow. 

 Invagination of glandular epithelium and some of the underlying con- 

 nective tissue. (From Kolster, " Die Embryotrophe placentarer Sauger," 

 Annt. Hefte, vols. xviii. and xix., 1902-3.) 



that they were composed of calcium oxalate. In Ruminants 



they are found in enormous numbers, but whether they form 



1 Quoted by Bonnet, " Ueber Embryotrophe," Munch, med. Woch., 1899. 



