CARBOHYDRATES AND FATS. 911 



other. The ratio of dextrose to nitrogen (D : N) is given as 3.65 to 

 1.* Special cases have been reported, however, in which the ratio 

 exceeded these figures. The general and specific symptoms observed 

 in diabetes mellitus closely resemble those observed upon dogs 

 suffering from pancreatic diabetes. It seems probable, therefore, 

 that in man the condition of diabetes may also be due in the first 

 place to some trouble in the pancreas which prevents it from giving 

 off its normal internal secretion. Whether or not the activity 

 of the pancreas is impaired in all these cases, the majority of those 

 who have studied the subject agree that the final difficulty lies 

 in the fact that the tissues, especially the muscular tissues, can 

 not utilize the sugar brought to them by the blood. Some writers 

 take an entirely different point of view, holding that the difficulty 

 lies not in the consumption of sugar by the tissues, but at the 

 other end, namely, in the proper handling or assimilation of the 

 sugar as it is absorbed from the alimentary canal, or in an increased 

 production of sugar in the body, f But assuming the correctness 

 of the usual view, it has been a question as to what part of the 

 process of glycolysis is affected. This process it will be remembered 

 is supposed to comprise two general stages, a series of preparatory 

 non-oxidative changes and a terminal series of oxidations yielding 

 CO 2 and H 2 O. Corresponding to this general point of view, some 

 authors have supposed that in the diabetic individual the activity 

 of the enzymes responsible for the preparatory changes is at fault, 

 while others have supported the opposite theory. At present 

 experiments on dogs exhibiting pancreatic diabetes seem to favor 

 the view that it is the second stage that is interfered with.J In 

 addition to the sugar found in the urine in diabetes, this secretion 

 may also contain considerable amounts of the acetone bodies, 

 namely, /3-oxybutyric acid, aceto-acetic acid, and acetone. It 

 is probable that these bodies represent intermediary products 

 in the metabolism of the fats of the body which escape oxidation, 

 and they appear in the urine of the diabetic either because the 

 power of the tissues to oxidize their fatty foods has also become 

 impaired or, as seems possible in the beginning, at least, simply 

 because in the loss of the power to utilize the energy of the carbo- 

 hydrates the tissues consume more fat, and whenever the fat 

 consumption is large it is likely to be incomplete, that is, some of 

 the intermediary products fail of oxidation and pass into the 

 general circulation (see p. 916). 



* Lusk, "Elements of the Science of Nutrition," Philadelphia. 

 t For literature on the metabolism of Diabetes, see Lusk, "Archives of 

 Internal Medicine," Feb., 1909; Magnus-Levy, "The Medical Record," Dec. 



3, 1910, and Minkowski, ibid., Feb. 1, 1913. 

 j Verzar, "Biochemische Zeitschrift," 66, 



75, 1914. 



