DIGESTIVE ORGANS AND THEIR ANATOMY. 299 



wholly connective tissue, and so far as structure is con- 

 cerned reminds one of the connective tissue of lymphatic 

 glands. In the meshes of this connective tissue is the 

 spleen pulp. This is loosely contained and may, when the 

 gland is cut, be more or less completely washed out, leav- 

 ing the framework exposed. When the spleen is cut and 

 this pulp forced out it looks very much like clotted blood, 

 which in fact it mainly is. Such pulp examined with a 

 microscope is seen to consist of ordinary red and white 

 blood corpuscles, the latter in relatively greater number 

 than in normal blood. Among these are many connective 

 tissue cells, found here, no doubt, for the same reason that 

 they occur in all the connective tissues. Among the white 

 blood corpuscles, however, there may be seen now and then 

 in fresh spleen pulp somewhat larger cells exhibiting to a 

 much greater extent amoeboid movements. These cells not 

 infrequently have in them" red corpuscles in all stages of 

 disintegration, and from this observation physiologists have 

 naturally come to the belief that these cells in the spleen 

 must be concerned in the destruction of red corpuscles. 

 These cells are called the splenic cells. 



The blood-vessels of the spleen are peculiarly interest- 

 ing. The artery on entering the spleen divides and sub- 

 divides, but the smaller arteries are not connected with 

 veins by means of capillaries as in other portions of the 

 body, but the arteries open abruptly, right into the spleen 

 pulp, thus allowing the blood to soak at large through the 

 interstices of the gland. On the other hand the veins orig- 

 inate as open ducts collecting the blood which has soaked 

 through the pulp. At the ends of these small arteries, that 

 is, just where they open abruptly into the spleen pulp and 

 to a somewhat smaller extent at the beginning of the veins, 

 there are situated little nodules of lymphatic tissue not un- 

 like the patches of Peyer in the intestines. These may be 

 exceedingly small, or may reach dimensions so as to be 

 plainly visible as whitish specks to the unaided eye. These 

 aggregations of white corpuscles are called the Malpighian 



