THE SPLEEN. 407 



rise to the opinion that one of the functions of the spleen is to 

 destroy them. The pigment-granules are found both without 

 and within the cells, and occasionally even stain the nodal 

 nuclei of the sustentacular tissue. The pigment is yellowish, 

 brown, or black, and there is enough of it to give a charac- 

 teristic dark color to the gross ap- 

 pearance of the spleen. In addition 

 to the pulp-elements mentioned, there 

 are, according to Fremke and Kolli- 

 ker, small, yellowish nucleated cells, 

 which are possibly young red blood- 

 globules. 



The pulp-substance thus described 

 has arterioles and capillaries ending 

 and veins beginning in it. The blood 

 flows from the former, through the 



i , ,-i -i-\ i i-i i i current; c, its continuation into the 



SpaCeS between the CellS, intO the lat- venous roots with incomplete walls; d, 



ter. Here is every opportunity, there- v 



fore, for the blood to recruit itself with new white corpuscles, 

 and to enrich itself with albuminous and pigmentary matter 

 from disintegrated red globules. The analyses of the blood 

 in the splenic vein seem to show that it does do this. 



Blood-vessels. We have already described, to a certain 

 extent, the general arrangement of the blood-vessels, but some 

 further particulars remain to be noticed. 



The splenic artery, the largest branch of the coeliac axis, 

 passes to the spleen in a course so tortuous as to shorten its 

 length in a straight line -by one -third. It enters the gastro- 

 splenic omentum, divides generally into six branches, and 

 passes into the spleen at the hilum, where, in common with the 

 vein, it becomes surrounded by the capsule of Malpighii. The 

 branches then rapidly subdivide and decrease in size, but with- 

 out anastomosing. When about two-tenths of a millimetre in 

 diameter they leave the veins and receive their sheaths of lym- 

 phoid tissue and Malpighian bodies, as has been described. 

 They then end for the most part in capillaries, which pass to 

 the Malpighian bodies and there break up in the way above 

 described. But there are other capillaries which pass into the 

 pulp-substance, where their walls gradually melt away, so to 

 speak, into the retiform tissue that surrounds them. If one 

 follows this change with a microscope, he will see the capil- 



