DUCTLES8 GLANDS. 365 



tions (sympexions) already described as existing in the thy- 

 roid. 1 



The pineal gland is situated just behind the posterior 

 commissure of the brain, between the nates, and is enclosed 

 in the velum interposition. It is of a conical shape, one- 

 third of an inch in length, and of nearly the color of the 

 pituitary body. It is connected with the base of the brain 

 by several delicate commissural peduncles. It presents a 

 small cavity at its base, and frequently contains in its sub- 

 stance little calcareous masses, composed of phosphate and 

 carbonate of lime, phosphate of magnesia and ammonia, and 

 a small quantity of organic matter. a It is covered with a 

 fibrous envelope, which sends processes into its interior. As 

 the result of the researches of M. Grandry, it has been found 

 to present a cortical substance, entirely analogous in its 

 structure to the pituitary body, and a central portion, com- 

 posed of the ordinary nervous elements found in the gray 

 matter of the brain. Its structure is regarded by Grandry 

 as very like that of the medullary portion of the suprarenal 

 capsules. 3 



It is difficult to classify organs, of the function of which 

 we are entirely ignorant; but the structure of the little 

 bodies just described certainly resembles that of the duct- 

 less glands. We have only indicated their anatomy to show 

 that their function is probably analogous to that of the other 

 organs of the same class. 



1 See page 360. 8 GRAY, op. rit., p. 528. 



3 GRANDRY, Glande pineale. Journal de fanatomie, Paris, 1867, tome iv., p. 

 405, et seq. 



