APPENDIX. 



Almen's Reagent. 1 Dissolve 5 grams of tannin in 240 c.c. of 

 50 per cent alcohol and add 10 c.c. of 25 per cent acetic acid. 



Ammoniacal Silver Solution. 2 Dissolve 26 grams of silver 

 nitrate in about 500 c.c. of water, add enough ammonium hydroxide 

 to redissolve the precipitate which forms upon the first addition of 

 the ammonium hydroxide and make the volume of the mixture up to 

 i liter with water. 



Arnold-Lipliawsky Reagent. 3 -This reagent consists of two 

 definite solutions which are ordinarily preserved separately and 

 mixed just before using. The two solutions are prepared as 

 follows : 



(a) One per cent aqueous solution of potassium nitrite. 



(b) One gram of />-amino-acetophenon dissolved in 100 c.c. of 

 distilled water and enough hydrochloric acid (about 2 c.c.) added 

 drop by drop, to cause the solution, which is at first yellow, to 

 become entirely colorless. An excess of acid must be avoided. 



Barfoed's Solution. 4 Dissolve 4.5 grams of neutral, crystal- 

 lized cupric acetate in 100 c.c. of water and add 0.12 c.c. of 50 per 

 cent acetic acid. 



Baryta Mixture. 5 A mixture consisting of one volume of a 

 saturated solution of barium nitrate and two volumes of a saturated 

 solution of barium hydroxide. 



Benedict's Solutions. 6 First Modification. Benedict's modi- 

 fied Fehling solution consists 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= 100 grams of anhydrous sodium car- 



1 Ott's precipitation test, p. 321. Determination of lactalbumin, p. 412. 



2 Salkowski's method, page 407. 



3 Arnold-Lipliawsky reaction, page 331. 



4 Barfoed's test, pages 31 and 313. 



6 Isolation of urea from urine, page 269. 



6 Benedict's modifications of Fehling's test, pages 28 and 309, and Benedict's 

 Method, page 368. 



416 



