The Hypophysis Cerebri. 297 



HISTORICAL. 



The mode of origin of the pituitary bodv has been an inter- 

 esting problem to embr}-ologists from the time of its discovery. 

 Since the solution of this problem, the much more difficult 

 one of its function or functions, and of the homologies of the 

 two structures entering into its formation, have encraged the 

 attention of embryologists. The very name pituitary body, by 

 which these combined structures are known, is a curious 

 vestige of an old belief, as pointed out previously. 



In the Atlas of Histologv, bv Klein and Xoble Smith, ^ 

 Chapter XLIII is devoted to what are commonly but erro- 

 neously called Ductless Glands. The opening paragraphs are 

 as follows : 



" These are : the frontal or large lobe of the pituitary gland 

 or hvpophvsis cerebri, the thyroid gland, the carotic gland of 

 Luschka, the suprarenal body and the coccygeal gland of 

 Luschka. These organs have the same developmental history 

 and resemble each other in many respects. They are all 

 derived from the hypoblast forming the wall of the fcetal 

 alimentary canal in its earliest stage, and are therefore of 

 epithelial origin. The hypophysis is an outgrowth of the 

 cephalic extremity of the alimentary canal (the upper wall of 

 the pharynx), the thyroid gland and carotic gland of its cervi- 

 cal part, the suprarenal body of the trunk part, and the coc- 

 cvgeal gland of the caudal end of the alimentary canal. 



In all of them the epithelial structures, derived from the 

 hypoblast, and the vascular connective tissue, derived from 

 the mesoblast, form the two chief constituent elements, and 

 in this respect they resemble other secreting glands. Unlike 

 these latter they do not possess any special ducts to carry 

 away the secretion, but this is probably effected by their 

 lymphatics." 



In an old edition of Foster and Balfour's Elements of 

 Embryology- is a brief review of the earlier literature on the 



1 Atlas of Histologv, by Klein and Noble Smith. Smithi, Elder & Co., 

 London. iSSo. 



* Elements of Embryology, bv Foster and Balfour. Macmillan & Co., 

 London. 1S74. Page 91. 



