THE Mi TABOLISM OF Tin: C UtBOHYDR \ ■ 



importanl of thes ncerns ili«' activities of the gastrointestinal appa- 

 ratus ai the time the sugar is given, Eor it 1ms been found thai if other 

 foodstuffs are being absorbed at the same time as the sugar, more of 

 the latter can be tolerated than when the sugar alone is being absorl 

 It has therefore been customary to give the sugar dissolved in water, 

 or in weak coffee, the firsl thing in the morning after the patient awal 

 i.e., at leasl twelve to sixteen hours after the lasl meal was taken. In 

 making these tests the urine voided before the sugar is estimated should 

 of course itself be thoroughly examined Eor reducing substances, and 

 tin 1 urine should be collected every ninety minutes and examined by a 

 reliable test (Benedict's or Nylander's).* 



Although a limit is set to the ability of the organism Eor retaining 

 sugar i mono- or di-saccharides), this does no1 seem to apply, in healthy 

 individuals at least, when starches (polysaccharides) are ingested. Thus, 

 it is a well-known fact that people can eat enormous quantities of pota- 

 toes or of bread without the appearance of any trace of reducing sub- 

 stances in the twenty-four-hour urine. On the other hand, urine collee 

 and examined at short intervals (every half hour > after taking large 

 quantities of polysaccharide-rich Eood will Erequently be found to contain 

 traces of reducing substances. 



For practical purposes it has been considered that an individual who 

 develops glycosuria after taking 100 gm. of glucose must he considered 

 .■is ;,t leasl a potential diabetic. In the light of the above results and 

 for many other reasons, there is, however, considerable doubt as to the 

 value of the assimilation lest. Thus, when a solution of glucose is 

 given orally, its rate of absorption will depend very largely on the 

 motility of the stomach. If this is normal, the solution will very quickly 

 find its way past the pyloric sphincter into the intestine, where it will 

 be rapidly absorbed. If. on the other hand, the pyloric sphincter does 



not open freely, the passage of the glucose into the intestine may he 



s,, delayed that no more is presenl in this place at one time than would 



be the case after an ordinary diet of polysaccharide. And even &i 

 the BUgar solution enters the small intestine, differences in the amount 

 of the intestinal contents with which it becomes mixed, in the extenl 



bacterial growth, and in the absorption pr ss, may very materially 



affeet the rate at which the glucose gains entry to the blood. 



Although often of doubtful diagnostic value, determination of the 

 assimilation limit is of considerable aid in controlling tin treat nn 



'Examination of normal individuals has shown that the assimilation limit for different 

 - -. >mewhat . 

 will be remembered, is the monosaccharide the coi 'he cane- 



sugar molecule, tl 

 the figures -. i m • 



tnd Uir sugai I in milk, the a 



