THE SPLEEN. 139 



tration of the walls of the arteries ; then we find that 

 at certain points this infiltration becomes quite ex- 

 tensive, the intercellular substance assuming the 

 character of recticular connective tissue ; and thus 

 distinct spheroidal or much elongated swellings are 

 formed either around or at one side of the arteries 

 these are the splenic nodules or Malpighian bodies. 



In some animals this infiltration is quite extensive 

 and continues along the arteries for a considerable 

 distance at either side of the nodules ; in others, as 

 in man, it is not very marked except in the nodules, 

 but may frequently be seen along the arteries ad- 

 jacent to them, in the form of narrow cellular 

 sheaths. The capillary net-work of the nodules is 

 connected with arterial twigs which either penetrate 

 from without, or are given off from the nodula 

 artery as it passes through the body. 



Let us now turn to the pulp. This is composed, 

 in the first place, of a multitude of irregular, fre- 

 quently anastomosing cords called pulp-cords be- 

 tween which, and bounded closely by them, lie, in 

 the second place, a series of branching channels 

 the cavernous veins. The pulp-cords joined on the 

 one hand to the nodules and infiltrated arterial 

 sheathes, and on the other to the connective-tissue 

 septa consist of a framework of delicate reticular 

 connective tissue, continuous with the sustaining 

 tissue of the nodules, the meshes of which .are in- 

 completely filled with various kinds of cells. Among 



