THE PINEAL BODY 



161 



Ellenberger ('87) no maintains that the pineal body in the 

 horse is very similar to a lymphatic gland. It is highly vascular; 

 in it are but a few nerve fibers and these are difficult to trace to 

 their origin. Flesch ('88) 123 studied the pineal body in the 

 horse, pig, dog, bat, and man. He was able to find brain sand 

 in man only. He does not believe that the organ is rudimentary, 

 but regards it as an epithelial structure. There are some nerve 



Fig. 77 Follicles and parenchyma of pineal body in man, showing concretion 

 of brain sand, according to Henle, 1879. 



fibers in it. Its relation to the size of the brain is not definite. 

 It has, in Flesch's opinion, a physiological action in mammals, 

 is very vascular, while its specific cells contain pigment granules. 

 It seems to be a secretory organ and may contain a heat-regulat- 

 ing centre. 



Edinger ('97) 1M found the pineal body in the higher mammals 

 to be formed of neuroglia cells. True nerve elements are 

 absent. Chauveau ('85) 64 observed groups of polyhedral cells 



MEMOIR NO. 9 



