In explaining the pancreatic form of diabetes Minkowski and von Mering assume that the pancreas supplies some substance, some fer ment which is necessary for the destruction of glucose in the body, and Lepine expresses the view that the blood contains a glycoly tic ferment serving for the destruction of sugar; that this is wholly or partly absent in animals after extirpation of the pancreas and in men affected with grave diabetes.
Formerly it was chiefly in the liver that the cause of diabetes was sought, although in extreme fatty degeneration of the liver after phosphorus poisoning and iu cirrhosis of the organ no glycosuria de velops. In order to decide this question Markusse subjected frogs to extirpation of the liver with the pancreas, and while glycosuria be gan in one or two days in frogs from which the pancreas alone was removed, no diabetes occurred when the liver also was removed.
The interpretation of this experiment is still a difficult one, and we are forced to assume either that a ferment is formed in the liver, which, without being sugar, is of importance for the development of diabetes ; or else that the liver destroys some substance in the blood, which remains in the latter after removal of the organ, and itself de stroys the sugar of the pancreatic form of diabetes. In many cases of obesity the disease of the pancreas has been studied by Balzer and others, besides the observers named, and the occurrence of fat ne croses in the organ has been frequently determined. But the pan creas was as frequently found apparently normal on microscopical and macroscopical examination. Nevertheless the hypothesis may be maintained (von Noorden) that purely functional disturbances of the pancreas, which cannot be recognized anatomically, are sufficient to produce glycosuria. In connection with the etiological considera tions it may be stated that it is improbable that the diabetes of obesity is of neurogenous origin, since corresponding affections of the medulla oblongata have thus far not been demonstrated.
The nutritive disturbance which is first and foremost in the dia betes of obesity is the early occurrence of disintegration of albumin, soon assuming considerable proportions, by which the amount of albumin, small as it is in the stage during which diabetes develops, is still further diminished. The increased disintegration of albumin in diabetes may be due to two causes : 1. The loss of nitrogen may be caused by defective nutrition, as the proteids of the food and the body albumin are no longer econo mized by the carbohydrates which are not burned up but changed into sugar. As the loss of calories derived from the carbohydrates must be replaced by transformation of albumin, and the calorie value of the albumin equals that of the carbohydrates, the great losses of albumin stfffered by the diabetic patient are explained.
When obesity is present the fat is likewise drawn upon for combus tion, perhaps at an earlier period, and the patient will lose fat as well as albumin and become thinner.
2. Loss of nitrogen may also result from a toxic disintegra tion of albumin, and while the decomposition just mentioned may be called physiological, this destruction of albumin must be considered as pathological and classed with that occurring in fevers, phos phorus poisoning, leukmmia, etc. Such a disintegration of albumin v. Mering claims to have demonstrated, since the diabetic patient observed by him, after deducting the amount of albumin transformed into sugar and passed in the urine, was still losing nitrogen in the stage in which a considerable quantity of beta--oxybutyric acid is excreted in the urine. Further confirmatory clinical observations are yet to be furnished.
Of importance in this connection might also be the fact demon strated by Kiilz, that some carbohydrates (levulose, inulin, cane sugar, milk sugar, etc.) are destroyed in the body of the diabetic patient, while others (grape sugar, starch, etc.) are not.
The sugar in the urine of the diabetic is grape sugar (glucose, dextrose) ; in a few rare cases only do we also find levorotatory sugars.
Besides, the power of destroying sugar is never completely lost, and even in the gravest cases thus far examined the quantity of sugar in the urine, though carbohydrates were supplied in abundance, was less than the amount of carbohydrates present in the circulation. According to Kiilz, the decomposition seems to be effected more largely in proportion as the ingestion of carbohydrates within a brief period is greater, and the losses by sugar formation augment the more the carbohydrates are distributed throughout the day. Additions of fat to the diet in diabetes can never increase the glycosuria, so that the loss of sugar by the patient can be reduced to the minimum by foods containing a moderate amount of albumin and a plentiful sup ply of fat. In like manner the combustion of sugar is as a rule aug mented by muscular labor and thus the glycosuria diminishes while the nutrition remains the same. In the same way as an ample supply of carbohydrates leads to their increased decomposition and thus economizes albumin, so does the augmented physiological consump tion of sugar by muscular labor, at least in the majority of cases.