736 SPECIAL PHYSIOLOGY. 



This hypothesis requires another mode of interpreting the microscopic 

 appearances just described, as to the alteration, agglomeration, and 

 encystment of the red blood-corpuscles in this organ. Since clusters 

 of altered red corpuscles are found in the splenic veins it has been 

 inferred that they proceed from the interior of the vessels and are 

 extravasated into the pulp when sections are made of this organ ; but 

 if the undefined spaces or lacunae, described by Gray and Billroth, 

 exist, the presence of these altered blood-cells in both the pulp and 

 the veins, and likewise the passage of the white nuclear and nucleated 

 elements of the splenic pulp into the veins, would be easily explained. 

 In support of the view that the red corpuscles decay in the spleen, it 

 is said that when the spleen is removed in frogs these corpuscles be- 

 come heaped or agglomerated in the blood itself. (Moleschott.) More- 

 over, as the quantity of fibrin in the blood of the splenic vein is greater 

 than in any other part of the venous system, it has been suggested 

 that this excess of fibrin is derived from the partial oxidation of the 

 globulin of the red corpuscles, which are relatively diminished in num- 

 ber in the splenic vein. The oxygen necessary for this change is 

 that belonging to the corpuscles. (Beclard.) 



Active and important chemical changes, however, must occur in the 

 capillaries and in the pulp of the spleen ; but these are not yet under- 

 stood. The chemical composition of the pulp, which resembles closely 

 that of the blood, is very complex. In every 1000 parts there are 

 750 of water, 242 of organic, and 8 of saline and earthy matters. 

 The organic substances consist chiefly of albumen, or some albuminoid 

 body ; besides this, there are traces of fat, and certain quantities of 

 pigment like that of the blood, with smaller quantities of inosite, 

 sarcin, leucin, tyrosin, xanthin, and even of uric acid. Soda and iron 

 are the chief inorganic substances. 



The variable size of the spleen under different conditions in the 

 same person, has attracted much notice. It reaches its largest dimen- 

 sions five hours after a meal, i. e., near the termination of the process 

 of chymification ; seven hours later, provided no food has been taken, 

 it is reduced to its smallest size, and is then also most deficient in 

 blood. The elasticity of the whole fibrous framework of the spleen, 

 including its proper coat, the sheaths of the vessels, and the trabeculse, 

 and also the large size of its veins and the absence of valves in them, 

 facilitate the distension of this organ with blood during the turgid 

 condition of the vascular system which results from the venous and 

 lacteal absorption of the products of digestion. The resiliency of 

 those elastic tissues will also favor the diminution of the organ in an 

 opposite condition of the system. But the pale, muscular fibres of the 

 spleen, which exist in abundance in the larger animals, and in smaller 

 number in man, may, by alternate conditions of relaxation and con- 

 traction under the influence of the sympathetic system, of of some direct 

 stimulus, materially assist in these remarkable changes of size, Elec- 

 trical currents passed through the spleen cause that organ to contract. 

 It has long been supposed that the alternate enlargement and diminu- 

 tion of the spleen serve a mechanical purpose, and that this organ acts 

 as a diverticulum to the entire portal venous system, or to the vessels 



