400 



THE SPLEEN. 



Fiir. 283. 



(Busk and Huxley). The meshes are densely packed with lymphoid 

 corpuscles, and the tissue is traversed by blood capillaries. 



The small arteries terminate 

 in capillaries, the walls of which, 

 as described by W. Mliller, after 

 a longer or shorter course, lose 

 their tubular character, the cells 

 composing them acquiring pro- 

 cesses and l>ecoming connected 

 by these with the connective 

 tissue cells of the pulp. In this 

 manner their blood flows directly 

 into the interstices of the pulp 

 tissue. The veins, which often 

 exhibit transverse markings, 

 perhaps due to a corresponding 

 arrangement of the retiform 

 tissue on tlieir surface, com- 

 mence in this tissue in the same 

 manner as the capillaries ter- 

 minate ; that is to say, the layer 

 of flattened cells which lines and 

 mainly composes their walls, on 

 being traced back, loses its 

 epithelioid character, and the 

 cells, becoming thickened and 

 enlarged and their nuclei pro- 

 minent, are found to 

 be, separated from each 

 other, but connected 

 by processes with, and 

 passing into those of 

 the pulp (fig. 285). The 

 small veins take a dif- 

 ferent course from the 

 corresponding arteries, 

 for they soon pass to 

 and are conducted 

 upon and within the 

 trabecular, freely join- 

 ing and anastomosing, 

 whereas the arteries 

 appear to have few or 

 no anastomoses within 

 the substance of the 

 oro-an. 



Fig. 283. — Small Artkry from Dog's 

 Spleen with Malpiohian Corpuscles at- 

 tached. 10 Diameters (Kiilliker). 



284. — Vertical Section of a Smaxl Superficial 

 Portion of the Human Spleen (from Kolliker). Low 

 Power. 



A, peritoneal and fibrous covering ; b, trabeculse ; c c, 

 IMalpighian corpuscles, in one of which an artery is seen 

 cut transversel}', in the other longitudinally ; d, injected 

 arterial twigs ; c, spleen-pulp. 



From the description 

 above given, it would 

 appear that the blood in 

 passing through the spleen 

 is brought into immediate 

 relation with the elements 

 of the pulp, and no doubt 



