APPENDIX 387 



10 to 20 gm. of crystallized sodium carbonate (or one-half the weight of the anhy- 

 drous salt) are added, together with a small quantity of powdered pumice-stone or 

 talcum, and the mixture heated to boiling over a free flame until the carbonate has 

 entirely dissolved. The diluted urine is now run in from the burette, rather rapidly 

 until a chalk white precipitate forms, and the blue color of the mixture begins to 

 lessen perceptibly, after which the solution from the burette must be run in a few 

 drops at a time, until the disappearance of the last trace of blue color, which marks 

 the end point. The solution must be kept vigorously boiling throughout the entire 

 titration. If the mixture becomes too concentrated during the process, water may 

 be added from time to time to replace the volume lost by evaporation. The cal- 

 culation of the percentage of sugar in the original sample of urine is very simple. 

 The 25 c.c. of copper solution are reduced by exactly 50 mg. of glucose. Therefore 

 the volume run out of the burette to effect the reduction contained 50 mg. of the 

 sugar. When the urine is diluted 1:10, as in the usual titration of diabetic urines, 

 the formula for calculating the per cent, of sugar is the following: 



' times 1000 equals per cent, in original sample, wherein X is the number of 



cubic centimeters of the diluted urine required to reduce 25 c.c. of the copper 

 solution. 



In the use of this method chloroform must not be present during the titration. 

 If used as a preservative in the urine it may be removed by boiling a sample for a 

 few minutes, and then diluting to its original volume. 



This solution will keep indefinitely and it is claimed by Benedict, that compari- 

 son with the polariscope and by Allihn's gravimetric process will show it to be more 

 accurate than any of the ordinarily used methods. 



APPROXIMATE QUANTITATIVE ESTIMATION with Fehling's solution. (One c.c. of 

 Fehling's solution is reduced by 5 mg. glucose.) 



Measure off 2 c.c. of Fehling's solution in a pipette and put in a test-tube or 

 small beaker and dilute with 20 c.c. of water. 



Bring the diluted Fehling's to boiling and drop in drop by drop the urine from 

 a dropping-bottle for which the number of drops per c.c. has been noted. Esti- 

 mating 20 drops to the c.c. if 2 drops of urine are required to reduce the copper it 

 would show a sugar percentage of the urine of 10. Four drops 5%, 8 drops 

 2 -5%> 16 drops 1.25%, 32 drops 0.6%, 64 drops 0.3%, 100 drops 0.2%. 



The Pancreatic Reaction of Cammidge in the Urine. 



Cammidge claims that there is a definite and important relationship between 

 his pancreatic reaction in the urine and disease of the pancreas. The results of 

 some workers go to support this view, particularly when considered in connection 

 with the examination of the faeces for neutral fat. 



The principle of the reaction depends upon the formation in the urine of a sub- 

 stance having the characters of an unfermentable pentose sugar after boiling with 

 hydrochloric acid. It is not present in the original urine as such, and forms an 

 osazone on treatment with phenylhydrazine, easily distinguished from the corre- 

 sponding compound of glucose. As the presence of glucose would seriously interfere 

 with the success of the reaction, all specimens of the urine examined must be care- 



