318 



SALIVAEY GLANDS AND 



included under this name. Ogata* considers that ft is derived 

 from the nucleus by the extrusion of its plasmosome, aft opinion" 

 which seems to be shared by von Ebner. f The studies of 



FIG. 262. CELLS FROM THE PANCREAS or NECTURUS IN VARIOUS STAGES OF SECRETION. 



A and .2?, show the appearance of cells which are nearly filled with secretion after a 



period of rest ; (7, after active secretion. Highly magnified. (After Math ews.) 



Mathews, however, show that at least in certain instances it is 

 distinctly fibrillar and that it is concerned with the mechanism 

 of secretion (see Fig. 3, page 3). 



ISLANDS OF LAN GERHANS. Most of the lobules of the pan- 

 creas contain, in addition to the acini and ducts, certain minute 

 collections of spheroidal or polyhedral cells which lie in the inter- 

 acinar connective tissue and which, though they possess the 

 appearance of secreting cells, are in no way connected with the 

 duct system. These cell groups are known as the islands of Lan- 

 gerhans (intraldbular cell groups). They are most abundant in 

 the splenic end of the gland (Opie). J 



The insular cells form a spheroidal group which is abundantly 

 supplied with blood capillaries. Occasionally the cells form col- 

 umnar strands between the capillary vessels but more frequently 

 they are irregularly disposed. Still more rarely they are so 

 grouped about a capillary vessel as to give a false impression of a 

 tubular structure. These cells possess a finely granular or retic- 

 ular cytoplasm and a central spheroidal nucleus. It is supposed 



* Arch. f. Physiol., 1883. f Kolliker's Handbuch 1902, Bd. iii, S. 250. 



% Johns Hop. Hosp. Bull., 1900. 



