118 



OBSERVATIONS UPON THE SPLEEN. 



strictor), Water Mokeson {Trigonocephalus piscivorus) , Copperhead {Trigonoceplidlus 

 contortrix), Ground Rattlesnake {Crotalophorus miliarms), Banded Rattlesnake (Cro- 

 talus durissus), and Water Rattlesnake (Crotalus adamanteus). [See Figs. 21 and 25.) 



In the Chelonians, the spleen varies much in size and appearance, even in indi- 

 viduals of the same species. In the Soft-shelled Turtle {Trionyx ferox), it is of 

 large size, kidney-shaped, and lies a little to the left of the median line of the 

 body, with its anterior concave border in contact with the inferior border of the 

 pancreas. {See Fig. 26.) 



Fig. 26. 



Spleen and pancreas of Soft-shelled Turtle [Trionyx ferox). A. Inferior portion of stomach. P, P, P. Pancreas. 

 S. Spleen. R. Small intestine. (Reduced one-half diameter.) 



In the Salt-water Terrapin [Emys terrapin), Chicken Terrapin {Emys reticulata), 

 and Yellow-bellied Terrapin {Emys serrata), it is smaller and more oval in shape. 

 {See Fig. 27.) 



Fig. 27. 



Spleen, pancreas, and stomach of Salt-water Terrapin {Emys terrapin), reduced one-half diameter. A. Inferior portion 

 of oesophagus. B. Stomach. 0. Small intestine. P. Pancreas. S. Spleen. 



The spleen is of very small size in all birds, generally oval in form, and situated 

 near the anterior extremity of the pancreas. 



In the Mammalia this organ is larger, and presents manifold diversities of form. 

 In all animals it may be distinguished, almost immediately, by its color alone. 



The researches of Professors Ecker and Kolliker, M. Beclard, Dr. Gray, and 

 other physiologists and chemists, have shown that the blood-corpuscles undergo 

 important changes in the spleen. 



If the function of the spleen be that of the formation and destruction of the 

 blood-corpuscles, it is reasonable to suppose that it should be much larger in warm 

 than in cold-blooded animals, because the number of the blood-corpuscles is greater, 



