Pathological Considerations 

 of the Pineal 



SMITH ELY JELLIFFE 



NEW YORK 



At the present time a pure pineal-body pathology cannot be written. 

 A large body of uncorrelated observations is obtainable but a satisfac- 

 tory systematic mode of dealing with them is not yet possible. The best 

 that can be done is first to summarize the various types of tissue involve- 

 ments that have been reported, and, second, to present what general 

 evidences of correlation there may be between changes in the histological 

 structure in the pineal body and disturbances of the bodily condition. 



The first series of observations may be regarded largely in the light 

 of pathological museum collecting; the second offer some opportunities to 

 determine possible roles that the pineal body may play in the scheme 

 of bodily organization, i. e., what in a general way may be said to 

 be the pineal functions. 



I. Minute consideration has been given to the histology of the pineal 

 body which has in general demonstrated the possibility of its playing a 

 dual role. It is a complex of organs rather than a single organ, the 

 general features of which have been most exhaustively dealt with by 

 Tilney and Warren (1919) and recently summarized by the writer 

 (Jelliffe, 1920). 



The phyletic, embryological, and histological evidence tends to show 

 that: 



[1] The pineal may be considered as a complex of organs of which 

 the subcommissural body may be considered an essential part. 



[2] That in this complex two separable structure types are present, 

 one of which apparently is undergoing regressive and involutive sub- 

 ordination, the other a progressive evolution apparently related to de- 

 veloping functional capacity. 



[3] That the former organs are possibly linked up with photic and 

 thermic stimuli, and the latter with chemical regulators of metabolism, 

 i. e., having an endocrin function. 



[4] That the consideration of the pathology may in a general way 

 be regarded as resulting (a) from changes in the pineal body itself, as 

 various forms of diminished, increased, or disharmonic capacity, or (b) 

 from the fact that new growths from the pineal structures by pressure 



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