PANCREAS. 193 



more than half of the cell. The granules thus seem to be a 

 stage in the formation of the secretion. Here, as elsewhere in 

 serous glands, secretory capillaries are present. 



In the secreting cell a structure has been described by 

 M. Nussbaum, in amphibians, as the Nebenkern (paranucleus). 

 This is a small body lying between the nucleus and membrana 

 propria in the non-granular part of the cell. It is oval or 

 twisted in form, and is stained easily. In animals that have 

 fasted for some time it seldom is found. The function and 

 significance of this structure are entirely unknown. 



-Intermediate duct 



..,- 



From a section of a dog's pancreas. X 175. 



In the centre of the end tubules one often finds flat cells, 

 the so-called centro-acinar cells (Langerhans). These must be 

 considered as a continuation of the epithelium of the inter- 

 calary ducts into the lumen of the gland tubules (Fig. 148). 



The tubules are surrounded by a membrana propria, which 

 contains basket cells. The processes of these are intimately 

 connected with the gland cells. 



In the centre of each lobule there can be observed with low 

 powers of the microscope light-staining areas. These were 

 described first by Langerhans, and are known generally as the 



13 



