No. 2.] CHANGES IX THE SPLEEX OF THE FROG. 411 



Rasa TeaapoitUja. 



curves are similar for the two sexes. The blood cnrves indi- 

 cate that the quantity of blood in the spleen does not vaciUale 

 as much in the escuUnta as in the temporaria spleen. 



The more typical character of the temporaria spleen may be 

 referred to the greater distinctness in the periods of the year's 

 cjcle, the fact that the}- have a dry food period in June, July 

 and August, a moist food period in September and October, 

 and that the sexual products, as we know for a catainty of the 

 males, are de\-eloped almost 

 entirely during the summer 

 months from June to Septem- 

 ber. The escuUnta, on the 

 other hand, keep to the swamps 

 and ponds for their nourish- 

 ment during the entire food 

 period, and the sexual products 

 are in process of formation dur- 

 ing the entire j-ear. All these 

 facts must have an inference 

 upon the character of the cells 

 in the spleen. 



There is, further, a certain 

 similarit}' in some curves of like 

 sexes. Thus the male spleens 

 are characterized by a greater 

 number of eosinophilous cells, 

 follicle cells, more c}-tozoa and 

 more protoplasm than the 

 female. The outlines of the 

 and fig" :rt? of ceU-di\Tsion are similar in the male spleens, 

 the elevations coming a month later in the escuUnta than in 

 the temporaria. spleen. The quantity of blood does not vary 

 as much in the male as in the female spleen. 



Characteristic for the female spleen is the greater amount <rf 

 pigment and the larger ir: * of blood, which vacillates 

 greatly in different months. I "Terence in chars rt er zri 

 mass of the sexual products r:-v .y explains these character- 





\ 



eosinophilous. 



nurse 



cell 



istics of the female spleen. 



'J twines of the size, ecsin- 



