386 HANDBOOK OF PHYSIOLOGY. 



is almost always found an hypertrophied state of the spleen or of the 

 lymphatic 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 

 corpuscles of the Uood, 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 

 together in roundish heaps, which may remain in this condition, or be- 

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

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

 puscles 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 en- 

 veloped by a cell-wall or not. 



(4.) From the almost constant presence of uric acid, in larger quan- 

 tities than in other organs, as well as of the nitrogenous bodies, xanthin, 

 hypoxanthin, and leucin, in the spleen, some special nitrogenous meta- 

 bolism 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 

 distended, and from the fact that it is generally small while gastric di- 

 gestion is going on, and enlarges when that act is concluded, it is sup- 

 posed 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 

 undergoes in certain affections of the heart and liver, attended with ob- 

 struction to the passage of blood through the latter organ, and by its 

 diminution when the congestion of the portal system is relieved by dis- 

 charges from the bowels, or by the effusion of blood into the stomach, 

 This mechanical influence on -the circulation, however, can hardly be 

 supposed to be more than a very subordinate function. 



It is only necessary to mention that Schiff believes that the spleen 

 manufactures a substance without which the pancreatic secretion cannot 

 act upon proteids, so that when the spleen is removed the digestive ac- 

 tion of the pancreatic juice is stopped. 



Influence of the Nervous System up^n the Spleen. When the spleen 



