468 APPENDIX 



irple- 



To each hour's specimen sufficient 25% sodium hydrate is added to give a pui 

 red colcr and the entire amount is then poured into a liter flask and made up to 

 looo c.c. A similar treatment is employed for the urine of the second hour. The 

 amount of drug eliminated in each hour is then determined by a colorimeter. 



Cabot has proposed the use of a series of 10 test-tubes containing solutions of 

 the drug representing from 5% to 50% of the drug dose, each tube containing 5% 

 more than the preceding one. These comparison solutions may be made up with 

 the patient's urine obtained at the time of emptying the bladder so that the con- 

 fusion which may obtain when water is used is avoided. It has recently been pro- 



FIG. 114. Rowntree and Geraghty modification of Hellige Colorimeter. 



posed to make the standards with water and use a piece of yellow glass for match- 

 ing. The urine to be tested made up to 1000 c.c. as previously described is then 

 poured into a test-tube of similar size and matched. 



In normal cases Cabot got 46% of the drug eliminated in the first hour, the 

 average for the second hour being 17%. The quantity of urine secreted in eithei 

 hour has no relation to the test, which is the percentage of drug eliminated. In 

 cases with serious kidney disease the amount of drug eliminated in the first hour 

 may range from 5 to 12%. 



When the question of the kidney involved arises, the urine must be taken by 

 ureteral catheterization or by a separator. 



Dunning has devised a simple inexpensive colorimeter for the drug excretion 



