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 condition may supervene. 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 de- 

 velops. 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 carbohydrate 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' 7 (Allenis). By these means 

 it becomes theoretically possible to investigate, on the one hand, other conditions which 

 will have an influence similar to removal of more of the gland, or, on the other, condi- 

 tions 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 

 ?vere case of diabetes, and in one experiment he succeeded in bringing 

 ibout 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 

 inimal after ligation of the portal vein. To the clinical worker the value 

 )f these results lies in the fact that they furnish experimental proof that 

 so-called latent case of diabetes that is, one that has a low tolerance 

 *alue for carbohydrates may be prevented from developing into a 

 severe case by proper control of the diet. 



