850 PHYSIOLOGY 



animal with a diabetic animal by means of its blood vessels, so as to allow 

 the healthy blood, presumably provided with the products of secretion of 

 the pancreas, to circulate through the diabetic animal, does not abolish 

 the condition of hyperglycsemia in the latter, though connection of the 

 portal vein of the healthy animal with that of the diabetic animal has, 

 according to Hedon, had the effect of stopping the condition of glycosuria. 

 Further work is required on this point. 



We thus see that the pancreas has a two-fold function, namely, the 

 secretion of a digestive juice into the intestine and the exercise by some 



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FIG. 367. (A) and (B) show an islet with the surrounding tissue in a resting gland (A) 

 and after exhaustion with secretin (B). In (A) the secreting acini are charged with 

 zymogen granules. In (B) these have entirely disappeared. On the other hand no 

 change is noticeable in the cells of the islet. In the latter the granular cells are 

 the 6 cells, and the clear hyaline cells are the a cells, (m) showing what are called 

 Minkowski granules. The granulation of this cell is regarded by Bensley as duo to 

 postmortem changes. 



means or other of an influence on general metabolism, the absence of which 

 is followed by the supervention of diabetes. Corresponding with this 

 two-fold function, two kinds of structures are present in the gland, the 

 secreting acini and the islets of Langerhans. These latter, though arising 

 in connection with the ducts, are solid masses of cells and have no com- 

 munication with the lumen of the ducts. According to Bensley and Lane 

 the islet cells may be divided into two varieties which have been given the 

 name of A and B cells, according as their granules are fixed respectively 

 by alcoholic or watery solutions.. It has been shown both by Bensley and 

 by Homans that these cells undergo no alterations when the gland is excited 

 to secrete by the injection of secretin. On the other hand,' if four-fifths 

 of the pancreas be removed, the remaining part may gradually become 

 inadequate to prevent diabetes, and Homans has shown that when under 

 these circumstances diabetes supervenes, the granules disappear from the 



