1903.] The "Islets of Zangerhans" of the Pancreas. 85 



experiment, until the pancreas ceased or almost ceased to secrete. The 

 animals were anaesthetised with morphia and A.C.E. mixture. 



In the toad, secretin was injected into the dorsal lymph-sac by a 

 hypodermic needle during 2 — 4 days. The effect of starvation was 

 observed in a stray cat, picked up in an emaciated condition and killed 

 immediately, and in toads which had been for several months in the 

 laboratory tank. 



In the resting glands of all the species the intermediate forms 

 described by Lewaschew were observed, the islets being formed 

 by an assimilation of the secreting epithelium to the centro-acinary 

 cells and the epithelium of the ductules, with later rearrangement 

 of the cells attended by formation of the wide tortuous blood- 

 capillaries. In the toad evidence was also found of reconstruction 

 of secreting alveoli from islets and of cell-multiplication in the islet 

 stage. 



The effect of exhaustion was in all cases the same — a very extensive 

 conversion of the secretory tissue of the gland into large islets, of 

 irregular outline, retaining obvious traces of their former alveolar 

 structure, and containing numerous intermediate forms. Specimens 

 have been obtained from a dog with the greater part of a lobule, and 

 from a toad with the greater part of the whole pancreas thus 

 converted. 



The effect of prolonged starvation was, on the whole, very similar 

 to that of exhaustion, but slighter in degree. 



Experiments on the dog* and rabbit were also made to observe the 

 effect of occluding the pancreatic duct. There resulted in all cases an 

 interstitial fibrosis. The areas of pancreas not destroyed assumed the 

 islet condition, but the preformed islets showed no special immunity from 

 destruction. 



The experiments leave the question of the function of the islets 

 undecided, but the results of occlusion of the duct are in favour of 

 Laguesse's view that they represent an internally secreting stage in the 

 life of pancreatic tissue. 



* On the dog only one experiment was made, in which the operation was 

 performed for other purposes by Professor Starling. 



