THE PANCKEAS 



401 



chemically; it is suggested that they indicate a twofold secretion (Lane). 

 The granules of the islet \cells of both types differ markedly also_lrom 

 those of the acinar cells. \The islets are of various sizes, ranging from 

 those with only a few or Wen a single cell to those with many cells 

 (3 millimeters in diameter) A The number of islets also varies greatly in 

 different individuals. Thus^e Witt (Jour. Exp. Med., vol. 8, 1906) 

 estimated the amount of islet tissue in three apparently normal subjects 



FIG. 375. PANCREATIC ISLET OF CAT. 

 7, endothelial cell; cap, capillary; be, red blood corpuscle. X 750. 



at 1-25, 1-50 and 1-125 of t 



of intravitam stains (neutralJred and janus green), Bensley succeeded in 



staining differentially the 

 counted from 13,000 to 56, 

 Anz., 43, 3, 1913) employed 

 secured shortly after death, 

 at 12 per milligram. In on 

 weight, he estimated the tot* 



e total volume of the pancreas. By means 



slets of the guinea pig's pancreas. He 

 00 in different specimens. Clark (Anat. 

 his method in a study of human pancreases 

 and estimates the average number of islets 

 male subject of 24 years and 140 pounds 



number of islets at 1,760,000 ; in another 

 of 29 years and 135 pounds weight, only 662, 166. Opie (Johns Hopkins 

 Hosp. Bull., 1900) first observed that the islets were more abundant in 

 the tail and least abundant in \ the head of the pancreas; this observation 

 is confirmed by both Clark and Bensley. Laguesse (Jour, de Physiol. et 



