PATHOLOGICAL METABOLISM OF DIABETES 273 



is well known, is capable of complete conversion into glucose in phlorhizin- 

 ized dogs and increases the glycosuria of human diabetes. The saponifi- 

 cation of a fat such as triolein or tristearin yields 1 molecule of glycerol 

 (mol. wt. 92) to 3 of oleic-acid (mol. wt. 284) or stearic acid (mol. wt. 

 256), a mixture in which 92 parts by weight are glycerol and 852 parts 

 fatty acid, or 92 are glycerol and 768 fatty acid. A fat such as triolein 

 would yield on saponification a mixture containing 9.7 per cent glycerol 

 while tripalmitin will yield 10.7 per cent glycerol. The former type of 

 fat predominating, we may calculate that 100 grams of fat catabolized in 

 the body may liberate above 10 gin. of glycerol and so yield about 10 

 grams of glucose in the body. 



Other substances besides carbohydrate, protein and fat that are capable 

 of yielding glucose in the body include lactic acid, but the above are the 

 chief sources of glucose supply under natural conditions. 



Deductions. If we assume in a given case of diabetes that all of the 

 glucose that enters the metabolic stream is derived from carbohydrate, 

 protein and fat and designate these as C, P and F respectively ; and if we 

 designate the total quantity of glucose liberated in the body from all 

 sources (endogenous and exogenous) as G, then approximately : 



G = C 4- .58 P + .1 F 



In the clinical literature of diabetes much is written of "carbohydrate" 

 tolerance. This frequently means the quantity of utilizable carbohydrate 

 that can be included in the diet without overtaxing the glucose tolerance. 

 Other glucose forming elements in the diet and the endogenous sources of 

 glucose supply are commonly neglected. A normal subject. S. A. B., body 

 weight 59 kg., studied by F. G. Benedict(c) showed on the fourth day of 

 fasting a catabolism of carbohydrate (glycogen) 25.17 gm., protein, 69.78 

 gm., fat, 144.72 gm. Taking the carbohydrate plus 58 per cent of the 

 protein plus 10 per cent of the fat we find that on that day 80 gm., or about 

 1.36 gm. per kg., of glucose could have been liberated in the body. On the 

 first day of fasting the same subject had catabolized carbohydrate 64.9, 

 protein 73.44, fat 126.4 gm. capable of yielding 120 grams of glucose or 

 2.0 gm. per kg. On diets that entail undernutrition and especially when 

 dealing with individuals that are impoverished in fat and must therefore 

 catabolize much protein, the gross errors that may arise from calculating 

 the glucose supply from the diet alone are apparent. 



Cause of Underconsumption of Glucose in Diabetes 



In 1788, Cawley reported' atrophy and stone of the pancreas in a case 

 of diabetes. The coincidence of diabetic symptoms and lesions of the 



