PATHOLOGICAL METABOLISM OF DIABETES 265 



mation of sugar in normal urine, emphasize the fallacies of the ordinary 

 clinical test. In border-line cases this procedure is of great value in settling 

 the question of the quantity of sugar excreted. However, having done so, 

 it still remains to be settled whether the quantity found is normal or ab- 

 normal. It is obvious that the size of the individual must be considered, 

 the time of excretion and also the rate at which glucose is entering the 

 metabolic stream. For a man weighing 75 kg. a total excretion of 1500 

 mg. per kg. ; for one weighing 50 kg., it is 30 mg. per kg. An excretion of 

 20 mg. per kg. in 6 hours is at the rate of 80 mg. per day. Also an ex- 

 cretion that is normal for one normal rate of glucose supply may be ex- 

 cessive for a lower normal supply rate, etc. For a true interpretation 

 of glycosuria it is necessary to consider the entire curve of glucose ex- 

 cretion by normal subjects under a series of supply rates. Benedict and 

 Osterberg(c) found the total sugar excretion, fermentable and unferment- 

 able, for an 18 kg. dog on a mixed diet to average 17 mg. per hour (i. e., 

 1 mg. per kg. hour). In fasting the fermentable fraction almost or 

 quite disappeared and the total sugar fell to 4.7 mg. per hour (0.26 mg. 

 per kg. hour). Benedict, Osterberg and Neuwirth working with a nor- 

 mal man (body weight 86 kg.) on mixed diets saw an excretion of 0.903 

 to 1.161 gm. of sugar per day, average 1 gm. per day. The same man on 

 "an empty stomach" excreted 79 mg. in 2 hours. The ingestion of 20 

 gm. of glucose then caused no increase of the glycosuria (i.e., a single dose 

 of 0.23 gm. per kg.). Doses of 40 gm. (0.47 gm. per kg.) caused an 

 increase of 100 mg. in 2 hours. Doses of 60 gm. (0.69 gm. per kg.) 

 caused increases of about 400 mg. in 2 hours. Reducing these figures for 

 dog and man to the basis of 50 kg. of body weight and 24 hours, we find 

 approximately : 



Excretion Rate 

 Period (gm. per 50 kg. per day) 



Fasting (dog) 24 hrs 0.3 



Mixed diet (man) 24 hrs 0.6 



"Empty stomach" ( man ) 2 hrs 0.6 



Glucose feeding 11.5 gm. (man) 2 hrs 0.6 



Glucose feeding 23.0 gm. (man) 2 hrs 1.3 



Glucose feeding 34.5 gm. (man) ...... 2 hrs 3.4 



While it is not certain that in these experiments the actual rate of glucose 

 absorption rose uniformly as a straight line in proportion to the quantities 

 of glucose given, it may have done so with these small to moderate doses. 

 In any case the data suggest an exponential excretion curve rising at first 

 very slowly from the horizontal and then bending rapidly upward the first 

 glucose increment causing no acceleration of the excretion, the second caus- 

 ing a definite acceleration, the third equal increment causing 4 times the 

 acceleration caused by the second. 



In this connection it will be recalled that in fasting, although the 



