4 HAND-BOOK OF PHYSIOLOGY. 



following data. (1.) The large size which it gradually acquires toward 

 the termination of the digestive process, and the great increase observed 

 about this period in the amount of the finely-granular albuminous plasma 

 within its parenchyma, and the subsequent gradual decrease of this mate- 

 rial, seem to indicate that this organ is concerned in elaborating the albu- 

 minous materials of food, and for a time storing them up, to be gradually 

 introduced into the blood, according to the demands of the general 

 system. 



(2.) It seems probable that the spleen, like the lymphatic glands, is 

 engaged in the formation of blood-corpuscles. For it is quite certain, 

 that the blood of the splenic vein contains an unusually large amount of 

 white corpuscles; and in the disease termed leucocythsemia, in which the 

 pale corpuscles of the blood are remarkably increased in number, there is 

 almost always found an hyper trophied state of the spleen or of the lym- 

 phatic glands. In Kolliker's opinion, the development of colorless and 

 also colored corpuscles of the blood is one of the essential functions of 

 the spleen, into the veins of which the new-formed corpuscles pass, and 

 are thus conveyed into the general current of the circulation. 



(3.) There is reason to believe, that in the spleen many of the red cor- 

 puscles of the blood, those probably which have discharged their office 

 and are worn out, undergo disintegration; for in the colored portions of 

 the spleen-pulp an abundance of such corpuscles, in various stages of 

 degeneration, are found, while the red corpuscles in the splenic venous 

 blood are said to be relatively diminished. This process appears to be as 

 follows. The blood-corpuscles, becoming smaller and darker, collect to- 

 gether in roundish heaps, which may remain in this condition, or become 

 each surrounded by a cell- wall. The cells thus produced may contain 

 from one to twenty blood-corpuscles in their interior. These corpuscles 

 become smaller and smaller; exchange their red for a golden yellow, 

 brown, or black color; and at length, are converted into pigment- 

 granules, which by degrees become paler and paler, until all color is lost. 

 The corpuscles undergo these changes whether the heaps of them are 

 enveloped by a cell- wall or not. 



(4.) From the almost constant presence of uric acid, as well as of the 

 nitrogenous bodies, xanthin, hypoxanthin, and leucin, in the spleen, 

 some nitrogenous metabolism may be fairly inferred to occur in it. 



(5.) Besides these, its supposed direct offices, the spleen is believed to 

 fulfil some purpose in regard to the portal circulation, with which it is in 

 close connection. From the readiness with which it admits of being dis- 

 tended, and from the fact that it is generally small while gastric diges- 

 tion is going on, and enlarges when that act is concluded, it is supposed 

 to act as a kind of vascular reservoir, or diverticulum to the portal system, 

 or more particularly to the vessels of the stomach. That it may serve 

 such a purpose is also made probable by the enlargement which it under- 



