THE METABOLISM OF THE CARBOHYDRATES 711 



all demonstrated by Sandemeyer, who found that if the greater part of 

 the pancreas was removed, the animals for some months, if at all, were 

 only- occasionally glycosuric, but later became more and more frequently 

 so, until at last the condition typical of complete pancreatectomy super- 

 vened. Similar results have more recently been obtained by Thiroloix 

 and Jacob, in France, and by Allen in this country. These investigators 

 point out that different results are to be expected according to whether 

 the portion of pancreas which is left does, or does not, remain in con- 

 nection with the duodenal duct. When this duct is ligated, atrophy of 

 any remnant of pancreas that is left is bound to occur, and this is asso- 

 ciated with rapid emaciation of the animal, diabetes and death. When 

 the remnant surrounds a still patent duct, a condition much more closely 

 simulating diabetes in man is likely to become developed one, namely, 

 in which there is, for some months following the operation, a more or 

 less mild diabetes, which, however, usually passes later into the fatal 

 type. 



It is, of course, difficult to state accurately what proportion of the 

 pancreas must be left in order that the above described qondition may super- 

 vene. Leaving a remnant amounting to from one-fifth to one-eighth 

 of the entire gland -is commonly followed by a mild diabetes, whereas 

 if only one-ninth or less is left, a rapidly fatal type develops. As in 

 clinical experience, the distinguishing feature between the mild and the 

 severe types of experimental pancreatic diabetes is the tolerance toward 

 carbohydrates. In the mild form, no glycosuria develops unless carbo- 

 hydrate food is taken; in the severe form, it is present when the diet is 

 composed entirely of flesh. It is thus shown that "by removal of a 

 suitable proportion of the pancreas, it is possible to bring an animal 

 to the verge of diabetes, yet to know that the animal will never of itself 

 become diabetic. . . . Such animals, therefore, constitute valuable 

 test objects for judging the effects of various agencies with respect to 

 diabetes" (Allen 18 ). It therefore becomes theoretically possible to in- 

 vestigate, on the one hand, other conditions which will have an influence 

 similar to removal of more of the gland, or, on the other, conditions 

 which might prevent the incidence of diabetes, even though this extra 

 portion of pancreas is removed. 



Allen has shown that the continued feeding of a partially depancreatized 

 dog with excess of carbohydrate food will surely convert a mild into a 

 severe case of diabetes, and in one experiment he succeeded in bringing 

 about the same transition by performing puncture of the medulla that 

 is, by creating an irritative nervous lesion. By none of the other means 

 usually employed to produce experimental glycosuria could the mild 

 case be made severely diabetic, although this was accomplished in one 



