366 



MANUAL OF PHYSIOLOGY. 



FIG. 156. SUPRARENAL CAPSULE. 



With regard to the function 

 of the suprarenal capsule, we 

 may say that nothing definite 

 is known. The cortical part 

 is said to resemble the lymph 

 follicles in structure, while the 

 central part, on account of its 

 numerous peculiar large cells, 

 and great richness in nerves, 

 has been explained as belong- 

 ing to the nervous system. 



THYROID BODY. 



The thyroid is made up -of 

 groups of minute closed sacks 

 imbedded in a stroma of con- 

 nective tissue, lined with a 

 single row of epithelium cells, 

 and filled with a clear fluid 

 containing mucin. In the adult 

 the sacks are commonly much 

 distended with a colloid sub- 

 stance and peculiar crystals, and 

 vertical section of the Suprarenal Cap- the epithelium has disappeared 



sule.-l. Cortex. 2. Medulla, a, Fibrous f rom their Walls. Although Said 

 capsule ; 6. External cell masses ; c, Col- , . , . , , , 



umnar layer; d, Internal cell masses; e, <*> be rich 111 lymphatics and to 

 Medullary substance, in which lies a large contain follicular tissue, positive 



proof of the relation of the thy- 



vein, partly seen in section/. 



roid body to the lymphatic system is still wanting. 



THYMUS GLAND. 



The functional activity of the thymus is restricted to that 

 period of life when growth takes place most rapidly. It is well 

 developed in the foetus, and increases in size for a couple of years 

 after birth ; but it gradually diminishes in bulk and loses its 



