PATHOLOGICAL METABOLISM OF DIABETES 267 



Diabetic Glycosuria 



In cases of severe diabetes the entire curve of glucose excretion may 

 be traced with supply rates rising from fasting levels to values no higher 

 than may be produced easily by oral administrations. The curve then ap- 

 pears foreshortened. Miss H. Felscher has -followed the total excretion 

 of sugar in the urine of diabetics weighing 40 to 50 kg. from the time 

 when as a result of diet limitations the urine became sugar "free," 

 through periods in which the diet was gradually increased until a defi- 

 nitely abnormal glycosuria was produced. When the patients were in 

 the non-diabetic state, the total sugar excretions (by the Benedict-Oster- 

 berg method) were usually between 300 and 600 mg. per day. As the 

 diets rose gradually at 1 to 4 day intervals, the curves showed at first (a) 

 no measurable rise at all, or (b) transient elevations with each diet ad- 

 dition followed by a return to the former level for the next day; or (c) 

 progressive but slight upward trends from the beginning; until in any 

 case a certain limit had been reached after which further additions caused 

 sharp upward bends or critical breaks in the curves. Thus a certain severe 

 case, weighing approximately 40 kg., showed an average excretion of well 

 below 1000 mg. of sugar until the total glucose equivalent of the diet had 

 mounted to 68 grams, when a further increment calculated as the equiva- 

 lent of 4 grams of glucose caused the excretion to rise by 3.8 to 4.0 grams. 

 Thus the severe diabetic appears to be capable of retaining glucose much 

 as a normal individual when the supply is within the limits of his toler- 

 ance, but when the supply exceeds this limit, he begins at once to excrete 

 an abnormal percentage of the excess. The transition from an almost 

 complete retention to an almost complete excretion may be very abrupt 

 and definable to within a few grams in sufficiently severe cases. Between 

 this type of case and the normal there is every grade of transition, the 

 difference between health and diabetes being one of degree. But even in 

 health the curve may break sharply at a certain point. 



Sugars Other Than Glucose in Diabetic Urine 



All of the material that is called sugar in the normal urine is ap- 

 parently not glucose, as stated above, but the absolute quantity of all sugars 

 other than glucose in the average normal urine is so slight that in com- 

 parison with the quantities of glucose that may occur in diabetic urine, 

 it may be neglected. Other sugars besides glucose may occur under excep- 

 tional conditions in quantities that are not negligible. Levulosuria, galac- 

 tosuria, pentosuria, lactosuria, etc., are well known phenomena. They 

 have been observed in non-diabetic individuals and they may doubtless 



