An Analysis of the Juxta-Neural Epithelial Portion of 

 the Hypophysis Cerebri, with an Embryological and 

 Histological Account of a Hitherto Undescribed Part 



of the Organ. 



By 

 Frederick Tilney. 



(From the Anatomical Department of Columbia University.) 



(With Plates V— XIX and 3 Figures in the Text.) 



In analyzing the several constituents which form the hypophysis 

 cerebri, the greatest difficulty has heen encountered in the region 

 where the neural and glandular components are in contact. The 

 earlier descriptions of the organ fail to recognize this region; the 

 more recent ones, although mentioning it, treat it in an uncritical and 

 almost casual manner. Herring [1 and 2] gives it the most adequate 

 treatment it has thus far received. He has noted two histologically 

 different areas in what he terms the pars intermedia. It will, however, 

 subsequently be shown in this paper that this observation cannot be 

 considered as a complete or satisfactory description of the complicated 

 juxta-neural epithelial portion of the gland. None of Herring's papers 

 gives evidence that he has perceived the actual conformation or 

 appreciated the extent, relations and genetic significance of this part 

 of the hypophysis. Doubtless these deficiencies would have been 

 avoided had the reconstruction method been employed. 



An analysis of the region in question must include consideration 

 not only of the neural constituents but also of that part of the 

 pituitary gland with which they are in contact. These neural con- 

 stituents comprise certain structures pertaining to the floor of the 



