XIX] THE SPLEEN 153 



Small tufts of splenic pulp injected with blue at 

 the ends of the capillaries of the pulp. 



Irregular masses of injected splenic pulp outside 

 the Malpighian corpuscles and lymphoid tissue of the 

 arteries where the capillaries open out into the pulp. 



If too great a pressure has been used in injecting, 

 instead of the tufts of injected pulp at the end of the 

 capillaries, irregular areas of the pulp or the whole of 

 it will be permeated with the Berlin blue ; the Mal- 

 pighiaii corpuscles and the lymphoid tissue of the arteries 

 will be free from injection unless the pressure used in 

 injecting has been very great. 



DEMONSTRATIONS. 



1. Section of spleen injected with Prussian blue 

 from the splenic vein under a low pressure. Observe, 

 the veins in the trabeculse filled with injection material; 

 the veins of the pulp more or less distinctly branching 

 out from the trabeculse; the irregular masses of injected 

 pulp at the ends of the veins. 



2. Section of spleen (dog or cat) ; nitrate of silver 

 injected into the artery so as just to reach the endings 

 of the artery. 



