THE SPLEEN'. 



2O5 



"the blood passes from the ampullae into the pulp space-;, then 

 through the pores into the walls of the veins to form columns of 

 blood discs which are pushed from the smaller to the larger veins 

 of the spleen." The pulp spaces usually contain very few blood- 

 corpuscles, in preparations fixed and prepared in the usual way, 

 since on removal from the animal the muscular tissue of the capsule 

 and trabeculae contracts and presses the blood from pulp spaces 

 into the veins. If, however, the muscular tissue of the spleen is 

 paralyzed before the tissue is fixed, numerous blood-corpuscles are 

 found in the pulp spaces. In the above account of the ultimate 

 distribution of the splenic vessels we have followed very closely the 

 recent observations of F. P. Mall. The accompanying diagram 

 (Fig. 164), slightly, though immaterially, modified from one given 



- Capsule. 



Intralobular trabecula. -- 



Artery to one of the ten ; 

 compartments. 



Intralobular artery. 



Interlobular trabecula. - - 



Intralobular trabecula. ! 



: 



Malpighian corpuscle. 



~ Intralobular venous 



spaces. 

 Intralobular vein. 



-- Ampulla of Thoma. 



-- Spleen pulp cord. 

 Interlobular vein. 



Intralobular vein. 



Fig. 164. Diagram of lobule of the spleen (Mall, "Johns Hopkins Hospital 

 Bulletin," Sept., Oct., 1898).' 



by F. P. Mall, shows clearly the trabecular and vascular systems 

 of a spleen lobule. In larger spleens there may be some two hun- 

 dred thousand of these lobules. In a dog weighing 10 kg. there 

 are on an average some eighty thousand (F. P. Mall). 



The splenic pulp consists of a reticulum, in the meshes of 

 which are found (i) fully developed red blood-cells; (2) now 

 and then nucleated red blood-cells; (3) in many animals giant 

 cells ; (4) cells containing red blood-corpuscles and the remains of 

 such, with or without pigment ; (5) the different varieties of white 

 blood-cells, especially a relatively large proportion of mononuclear 

 leucocytes. Pigment granules, either extra- or intracellular, also 

 occur in the splenic pulp. The pigment probably originates from 

 disintegrating erythrocytes. Besides these are found, especially in 



