THE PARS BUCCAL1S OF THE HYPOPHYSIS 103 



in the case of the complete absence of the epithelial hypophysis 

 the neural lobe underwent an abortive development, while the 

 other portion of the infundibular process, the pituitary floor, 

 normally in contact with the epithelial component, retained its 

 membranous character in sharp contrast to the thickened wall 

 normally displayed. Further studies of the 'partial ' albino indi- 

 cated that the atypically placed epithelial fragment apparently 

 is able to 'stimulate' the adjacent neural tissue to form a struc- 

 ture, simulating histologically the typical neural lobe. Doubt, 

 however, was cast upon the functional sufficiency of this 'novel' 

 neural lobe, since the animals displaying this anatomical arrange- 

 ment failed to metamorphose in contrast to those in which this 

 epithelial fragment attained contact, though but slight, with 

 the true neural lobe, a failure not entirely attributable to the 

 smaller size of this epithelial remnant. From this it would 

 appear that the neural tissue comprising the pars nervosa of 

 the pituitary enjoys the same functional specificity as do the 

 other glandular tissues of the body. 



It is a pleasure to acknowledge the aid which I have received 

 throughout this work from Doctor Evans. The many helpful 

 suggestions and the encouragement which he has given during 

 the progress of the work and in the preparation of the manuscript 

 have been invaluable. To Mrs. Smith and Mr. Lee for their 

 aid in the preparation of many of the models I am much in- 

 debted. Acknowledgment is made for the services rendered 

 by our photographer, Mr. Matthews, and by our artist, Mr. 

 Sweet. 



6. SUMMARY 



1. The frog and the toad tadpole, because of the accessi- 

 bility of the epithelial hypophysis in the early larval stages and 

 the prolonged survival of the animals suffering the loss of this 

 gland, has proved of great value in the institution of hypophysial 

 disturbances and in the subsequent analysis thereof. 



