ANATOMY AND EMBRYOLOGY 



233 



found cells that are nongranular: the so-called principal cells, which during 

 pregnancy, according to Erdheim and Stumme, develop into the so-called 

 pregnancy cells. 



Posteriorly the anterior lobe is delimited from the so-called pars inter- 

 media by a poorly vascularized layer of connective tissue. The especial 

 histological character of the pars intermedia has been emphasized by Her- 

 ring. Here are found follicle-like pictures filled with colloid. This cellular 

 layer has also been called the cork layer or Peremeschko's medullary layer. 

 Here lies also the so-called Rathke's cyst. 



The posterior lobe is made up of glial tissue 

 and scattered cells, the character of which has 

 not as yet been established, and of nerve fibers. 



The hypophysis of man undergoes character- 

 istic alterations during pregnancy. First Comte, 

 in six pregnant women, found enlargement of 

 the hypophysis and multiplication of all the sorts 

 of cells. Later Erdheim and Stumme made a 

 careful study of the alterations. According to 

 both these authors the enlargements affect only 

 the anterior lobe. The differences in size are 

 very appreciable. While the weight of the 

 hypophysis in a nuHipara is about 61.8 cgm. 

 on the average, Erdheim and Stumme found it 

 to be on the average 84.7 cgm. in primiparae 

 and 106 cgm. in multipart. ^ 



Through its position the hypophysis shows 

 special relations to the chiasm of the optic 

 nerves and to the third and sixth cranial nerves. 



The embryological development of the hypo- 

 physial apparatus is shown in the following 

 three sketches, which are taken from the works 

 of Erdheim and of Mihalkovic. 



FIG. 



32. Development of the 

 hypophysis. 



i = infundibulum. 



h = Rathke's pouch. 



x = boundary between epithelium originating from the primary 



ectodermal oral diverticulum and the entodermal head-gut. 

 Pi = solid process (anterior lobe) . 



g = hypophysial duct. 



x = original insertion of the hypophysial duct. 

 pi = process of the grown-out [ausgewachsen] normal hypophysis. 



x = collection of accumulations of squamous epithelium, probably 

 remnants of the hypophysial duct originating from the epi- 



