EXPERIMENTAL DIABETES 349 



excretion of nitrogen to fall and the D : N ratio may become 

 7 or even higher. 



All the other symptoms of severe diabetes are also produced 

 by the extirpation. We have noticed that the desire for water 

 is especially marked where some pancreatic tissue has been left, 

 and the D : N ratio is therefore less than 3 . 



The preliminary rise in the sugar excretion is no doubt due 

 to the elimination from the organism of stores of sugar or 

 sugar- yielding substance derived from the previous diet. Thus 

 it was noticed by Minkowski that the height of the sugar 

 excretion about the third day after the operation was greater in 

 dogs which had been well fed previous to the operation than in 

 those which had been poorly fed. At first sight it may be 

 difficult to imagine how, if this explanation of the preliminary 

 rise be correct, the maximal excretion should not exist on the 

 first day after the excision of the gland; if, however, it be 

 remembered that it is from the withdrawal of an internal 

 secretion which normally destroys sugars in the organism that 

 the diabetes results (see p. 339), the apparent anomaly disappears, 

 for an excess of this secretion might be present in the blood when 

 the gland is removed, so that several days might elapse before it 

 was all used up. In support of this explanation, may be quoted an 

 observation of Minkowski's, that in one dog it was not until three 

 days after the excision of the gland that any sugar at all appeared 

 in the urine, and the gland on excision was found to be hyperaemic 

 and apparently very active. We also found very little sugar 

 in the urine the day after the removal (incomplete) of the gland 

 in one dog, with a very large excretion next day. 



With regard to the source of the sugar in pancreatic diabetes, 

 there can be no doubt that at first it comes from stored-up 

 carbohydrate. If, a few days after the operation, the animal 

 be killed by bleeding and an examination of the liver for 

 glycogen immediately made, only traces will be found, and this 

 is so not only when, previous to death, no food had been given, 

 but also after the liberal ingestion of food. For example, we 

 could find no trace of glycogen (Pfltiger's method) or of dex- 

 trose in the liver of the above-mentioned depancreated dog, 

 which had been fed with 200 grm. of flesh each day for several 

 days before death. Minkowski has noted the same thing for 

 dextrose ; i.e. it does not Cause glycogen to be deposited. The 



