41 8 PHYSIOLOGICAL CHEMISTRY. 



(b) Five grams of sulphanilic acid and 50 c.c. of hydrochloric 

 acid in i liter of distilled water. 



Solutions a and b should be preserved in well stoppered vessels 

 and mixed in the proportion i : 50 when required. Green asserts 

 that greater delicacy is secured by mixing the solutions in the pro- 

 portion i : 100. The sodium nitrite deteriorates upon standing 

 and becomes unfit for use in the course of a few weeks. 



Esbach's Reagent. 1 Dissolve 10 grams of picric acid and 20 

 grams of citric acid in i liter of water. 



Fehling's Solution. 2 Fehling's solution is composed of two 

 definite solutions a cupric sulphate solution and an alkaline tartrate 

 solution, which may be. prepared as follows : 



Cupric sulphate solution = 34.65 grams of cupric sulphate dis- 

 solved in water and made up to 500 c.c. 



Alkaline tartrate solution = 125 grams of potassium hydroxide 

 and 173 grams of Rochelle salt dissolved in water and made up to 

 500 c.c. 



These solutions should be preserved separately in rubber-stop- 

 pered bottles and mixed in equal volumes when needed for use. 

 This is done to prevent deterioration. 



Ferric Alum Solution. 3 A cold saturated solution. 



Folin-Shaffer Reagent. 4 This reagent consists of 500 grams 

 of ammonium sulphate, 5 grams of uranium acetate and 60 c.c. of 

 10 per cent acetic acid in 650 c.c. of distilled water. 



Furfurol Solution. 5 Add i c.c. of furfurol to 1000 c.c. of dis- 

 tilled water. 



Gallic Acid Solution. 6 A saturated alcoholic solution. 



Guaiac Solution. 7 Dissolve 0.5 gram of guaiac resin in 30 c.c. 

 of 95 per cent alcohol. 



Gunzberg's Reagent. 8 Dissolve 2 grams of phloroglucin and i 

 gram of vanillin in 100 c.c. of 95 per cent alcohol. 



Hammarsten's Reagent. 9 Mix i volume of 25 per cent nitric 

 acid and 19 volumes of 25 per 'cent hydrochloric acid and add 



1 Esbach's method, page 366. 



2 Fehling's method, page 367. Fehling's test, pages 27 and 308. 



3 Volhard-Arnold method, page 396. 



4 Folin-Shaffer method, page 372. 



r> Mylius's modification of Pettenkofer's test, pages 156 and 326. v. Udransky's 

 test, pages 156 and 326. 



6 Gallic acid test, page 225. 



7 Guaiac test, pages 178, 196 and 322. 



8 Test for free acid, page 123. 



" Hammarsten's reaction, pages 155 and 325. 



