THE THYMU8 GLAND. 



983 



are of large size, arise in the substance of the gland, and are said to terminate in 

 the internal jugular vein. The nerves are exceedingly minute ; they are derived 



Artery. 



Vein 



Artery. 



FIG. 542. Minute structure of the thymus gland. Follicle of injected thymus from calf, four days old, 

 slightly diagrammatic, magnified about 50 diameters. The large vessels are disposed in two rings, one of which 

 surrounds the follicle, the other lies just within the margin of the medulla. (Watney.) A and B. From thy- 

 mus of camel, examined without addition of any reagent. Magnified about 400 diameters. A. Large colorless 

 cell containing small oval masses of haemoglobin. Similar cells are found in the lymph-glands, spleen, and 

 medulla of bone. B. Colored blood-corpuscles. 



from the pneumogastric and sympathetic. Branches from the descendens hypo- 

 glossi and phrenic reach the investing capsule, but do not penetrate into the sub- 

 stance of the gland. 



