1126 



THE ORGANS OF VOICE AND RESPIRATION. 



Dr. Watney has recently made the important observation that haemoglobin is 

 found in the thymus either in cysts or in cells situated near to or forming part 



,Vein. 



Artery. 



FIG. 715. Minute structure of the thymus gland. Frllirk> 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. 



of the concentric corpuscles. This haemoglobin varies from granules to masses 

 exactly resembling colored blood-corpuscles, oval in the bird, reptile, and fish ; 

 circular in all mammals except in the camel. Dr. Watney has also discovered 

 in the lymph issuing from the thymus similar cells to those found in the gland, 

 and, like them, containing haemoglobin either in the form of granules or masses. 

 From these facts he arrives at the physiological conclusion that the thymus is one 

 source of the colored blood-corpuscles. 



Vessels and Nerves. The arteries supplying the thymus are derived from 

 the internal mammary and from the superior and inferior thyroid. The veins 

 terminate in the left innominate vein and in the thyroid veins. The lymphatics 

 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 

 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. 



