234 THE DISEASES OF THE HYPOPHYSIS 



thelium of the oral diverticulum, while the epithelium of the 

 hypophysial duct is cubical. 



The nervous lobe of the hypophysis originates from the diencephalon. 

 Here there develops a pouch-like protrusion (processus inf undibularis) , which 

 during the fourth week adjoins a similar pouch originating from the epithe- 

 lium of the oral diverticulum (Rathke's hypophysial pouch). In the lower 

 classes of animals there exists an intimate spatial relationship between the 

 two, due to the fact that the infundibular peduncle, which in these animals 

 is much better developed, is overlain in a cup-like manner by the epithelial 

 part (see Edinger, Bau der nervosen Zentralorgane des Menschen und der 

 Tiere, 2, Bd. 7 Edition, 1908). In man this intimate relationship between 

 anterior and posterior lobes is by no means so extensive. Here principally 

 the posterior lobe is very much less well developed. 



The question as to whether the pars intermedia belongs to the anterior 

 or to the posterior lobe seems to me, according to what I can find in the 

 literature as to this subject, as yet not cleared up. At all events the facts 

 are important that on separation of the anterior lobe from the posterior the 

 pars intermedia always remains with the posterior & fact also mentioned 

 by Gushing and that, as had already been mentioned, the anterior lobe and 

 the pars intermedia are always separated by a layer of connective tissue. 

 This question seems to me to be a very important one from the clinical 

 standpoint. As is known, the posterior lobe and the pars intermedia contain 

 a substance that increases blood-pressure and acts as a diuretic, a substance 

 that in its action shows a certain similarity to adrenalin. It is, therefore, not 

 impossible that the pars intermedia possesses in its relation to the nervous 

 system similar embryological relations to those which have been demon- 

 strated for the chromafrin tissue. 



The analogy in the development of the glandular lobe of the hypophysis 

 with that of the development of the thyroid is apparent. Both originally are 

 glands with external secretion. Just as is the case with the hypophysial 

 duct, the ductus thyreoglossus undergoes atrophy ; this also leaves behind cell 

 accumulations which consist chiefly of stratified plaster epithelium. Accord- 

 ing to the recent investigations of Haberfeld the hypophysial duct may, espe- 

 cially when there are malformations of the skull, persist. This has also been 

 observed in acromegaly (Ettore Levi). It is of especial significance for the 

 pathogenesis of acromegaly, as we shall see later, that accumulations of 

 typical glandular epithelium may be found on the roof of the pharynx as well 

 as along the persistent craniopharyngeal canal, from which accumulations 

 may be formed adenomata. 



The glandular anterior lobe of the hypophysis is a triie ductless gland. 

 The opinion has been expressed that its secretion streams off through the 

 posterior lobe. Against this speaks first the separate blood supplies, then 



