THE PIXKAL BODY 2()3 



cells to those of the adreiuil inedulhi suggests an eiidocrhie fuiictiuii, 

 thouijh experimental evidence is lacking. 



PARAGANGLIA. 



In \ari()us organs of the body, occasional syini)atlietic ganglia 

 are fonnd associated with a small mass of chromaffin cells resembl- 

 ing those of the carotid gland, or adrenal medulla. These glandular 

 masses, known as i)araganglia, have a histological structure suggest- 

 ing an endocrine function, but as yet there is no exi^erimental 

 evidence as to their function. 



THE PINEAL BODY. 



The pineal body received its name because of its resemblance to 

 a pine cone. It is also known as the epiphysis cerebri, and is located 

 in the dorsal region of the brain between the cerebrum and cere- 

 bellum, where it appears as a small red body. It is attached to the 

 third ventricle by a stalk and is surrounded by the pia mater. 

 Islands of epithelioid cells, separated and surrounded by capillaries, 

 are embedded in a connective-tissue stroma. Some of the cells 

 resemble cytons of multipolar nerve cells without any processes. 

 A network of fibers from the sympathetic system pass through the 

 connective tissue. It has been assumed that this glandular tissue 

 has an endocrine function, because it has been observed that a 

 tumorous growth of the pineal gland appears to be associated with 

 an unusually early maturing of the sex glands. That is, it has been 

 assumed that the normal pineal secretes a hornione that delays 

 the too-rapid development of sex organs. However, exjjeriments 

 give conflicting results. 



Other Endocrine Glands Already Considered.— The islands of 

 Langerhans in the pancreas secrete insulin controlling metabolism 

 of carbohydrates. The endocrine nature of the ovary and testis 

 has also been indicated. The liver has also had attributed to it an 

 endocrine activity. Possibly all cells have an endocrine activity to 

 some extent, but as yet only the more conspicuous organizations 

 have been demonstrated experimentally. 



REFERENCES. 



Adams, H. E., Kuder, A., and Richards, L. 1932. The endocrine glands 

 and molting in Triturus viridescens, Jour. Exp. ZooL, 63, 1. 



Addison, W. H. F., and Richter, M. N. 1932. A note on the thyroid gland 

 of the swordfish, Biol. Bull., 63, 472. 



Allen, E. 1932. Se.x and Internal Secretions, Baltimore, Williams & Wilkins 

 Company. 



