VASCULAR OR DUCTLESS GLANDS. 75 



semi-fluid substance composed of numerous small cells resembling lymph 

 corpuscles. The spleen pulp is a dark red, semi-fluid substance, of a soft 

 consistence, contained in the meshes of the trabeculae. In it are found 

 numerous corpuscles, like those observed in the Malpighian bodies, blood 

 corpuscles in a natural and altered condition, nuclei and pigment granules. 

 Function of the Spleen, Probably influences the preparation of the 

 albuminous food for nutrition ; during digestion the spleen becomes larger, 

 its contents are increased in amount, and after digestion it gradually dimin- 

 ishes in size, returning to the normal condition. 



The red corpuscles are here disintegrated, after having fulfilled their 

 function in the blood ; the splenic venous blood containing relatively a 

 small quantity. 



The white corpuscles appear to be increased in number, the blood of the 

 splenic vein containing an unusually large proportion. 



The spleen serves also as a reservoir for blood when the portal circula- 

 tion becomes obstructed. 



The nervous system controls the enlargement of the spleen ; division of 

 the nerve produces dilatation of the vessels, stimulation contracts them. 



The Supra-renal Capsules are triangular, flattened bodies, situated 

 above the kidney. They are invested by a fibrous capsule sending in 

 trabeculse, forming the framework. The glandular tissue is composed of 

 two portions, a cortical and medullary. The cortical being made up of 

 small cylinders lined by cells and containing an opaque mass, nuclei and 

 granular matter. The medullary consists of a fibrous network containing 

 in the alveoli nucleated protoplasm. 



The Thyroid gland consists of a fibrous stroma, containing ovoid 

 closed sacs, measuring on the average ^ of an inch, formed of a delicate 

 membrane lined by cells; the contents of the sacs consist of yellowish 

 albuminous fluid. 



The Thymus gland is most developed in early life and almost disap- 

 pears in the adult. It is divided by processes of fibrous tissue into lobules, 

 and these again into follicles which contain lymphoid corpuscles. 



The functions of ttie vascular organs appear to be the more complete 

 elaboration of the blood necessary for proper nutrition ; they are most highly 

 developed during infancy and embryonic life, when growth and develop- 

 ment are most active. 



