68 LABORATORY METHODS OF 



The splenic artery enters the spleen at the hilum 

 and passes up the trabeculae for a certain distance, 

 and then leaves them and passes into the splenic 

 pulp ; here the artery loses its outer coat and con- 

 tinues as the lymphoid tissue of the spleen. In this 

 place the adenoid tissue collects into a dense mass and 

 the mass is called the Malpighian corpuscle of the 

 spleen. Here the germ center is found. The veins 

 begin where the artery ends and pass to the trabeculae, 

 where they pass out of the organ by following the tra- 

 beculae to the hilum. A few lymphatics are found in 

 the capsule and trabeculae. The nerves of the glands 

 are few in number, and are usually distributed to the 

 blood vessels. 



Exercise No. 41. Harden the spleen; mount, stain 

 and examine. Follow the formalin method; stain 

 with eosin and haematoxylin. 



Exercise No. 42. Do the same with a lymph nodule. 

 THE THYMUS. 



The thymus is a gland. In early life it is mostly 

 ephithelial in nature, and in later life it becomes a 

 lymphoid gland, presenting all the characteristics of 

 the spleen. The blood vessels and nerves are found 

 in the trabeculae and send other branches into the 



