Au Analysis of tlie Juxta-Neiiral Epithelial Portion etc. 269 



to remove the pars tuberalis are quite obvious. It is safe to say 

 that ko complete hypophysectom}^ has been or can be performed upon 

 the dog leaving- the floor of the third ventricle intact. The removal 

 of the pars tuberalis means the removal of the saccular eminence; 

 this latter is by no means indifferent tissue but contains part of the 

 ganglia supraoptica of Kölliker besides a number of scattered groups 

 of nerve cells. In this light the remarkable train of symptoms de- 

 scribed as consequent upon the complete removal of the hypophysis 

 must be received with considerable reservation since it is impossible 

 at present to state how much of this extensive syndrome is due to 

 removal of the pituitary gland and how much results from laceration 

 or destruction of the tuber cinereum. This position should impress 

 itself all the more forcibly upon the experimentalists since our know- 

 ledge concerning the functional significance of the tuber cinereum is 

 so meagre and unsatisfactory. 



3. Adult Eabbit. Specimen no. H 70 (plate IX, figs. 9 and 10). 



In the rabbit the three neural elements of the hypophysis may 

 be easily distinguished. The saccular eminence of the tuber cinereum 

 has practically the same relations as in the cat and dog. Its ventro- 

 cephalic surface [Oh] is more sharply convex while its caudal sur- 

 face is less in altitude. Its lateral extremities are free from the 

 overlying lateral eminences. Some differences are seen in the iufun- 

 dibulum due to the fact that the latter is not as pronounced in its 

 proximal portion as in the cat or dog. Its stem, however, is well 

 marked and passes into the expanded infundibular process. The 

 recessus tuberis is typical in its character and relations, but there is 

 no cavity in the infundibular process. 



The epithelial elements are three in number. The pars tuberalis 

 invests the saccular eminence and is closely adherent to it. The pars 

 infundibularis [13 a] surrounds the infundibular process and the stem 

 of the iufundibulum. By this latter investment the processus infun- 

 dibuli is brought into relation with a dense layer of epithelial cells 

 on its ventro-cephalic and ventral aspects; its caudal surface is covered 

 by a much attenuated stratum of the same type of epithelial cells. 

 An irregular residual lumen [15] almost completely separates the 



