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Society Proceedings (122). 



material. Outside this space was a zone of pars intermedia cells. 

 Posteriorly these cells were separated from the base of the brain 

 by scar tissue, but anteriorly, at the point where the connective 

 tissue portion of the floor of the ventricle joined the normal floor, 

 there was no intervening scar tissue. Here a mass of pars in- 

 termedia cells, continuous anteriorly with pars anterior cells, 

 had invaded the base of the brain so that the cells lay immediately 

 under the ependymal lining. The majority of these cells were 

 chromophobe and arranged in alveoli containing colloid, but 

 among them were occasional eosinophiles similar to those in the 

 adjacent anterior lobe. 



In other experiments I have produced polyurias that ended 

 in the third, fourth or fifth month, but sections have shown that 

 the stalk division had not been made sufficiently high to detach 

 all the pars tuberalis cells from the base of the brain, and that this 

 epithelium had proliferated above the scar. Only in Dog 4 were 

 all of these cells detached with the gland. The sections of this 

 animal are interpreted as meaning that the anterior and superior 

 portion of the pars intermedia reunited with the uninjured floor 

 of the third vertricle without any intervening scar tissue, so that 

 there was nothing to prevent pars intermedia products from passing 

 into the ventricle, if that be the method of secretion. 



I am not ready to interpret these findings as they effect the 

 question of the cause of experimental polyuria. They indicate 

 that a stalk division high enough to detach all epithelium from 

 the base of the brain and completely destroy the tuber cinereum 

 does not necessarily result in a permanent polyuria, and that the 

 true permanency of previously reported results of such experiments 

 is open to question. 



