THE JOURNAL OF PHARMACOLOGY 



Nessler's reagent for aldehyde. Alde- 

 hydes when treated with Nessler's am- 

 monia reagent (q. s.) or with a solution 

 of potassium mercuric iodide and baryta 

 water, yield brownish-black precipitates, 

 which differ from the precipitates caused 

 by the same reagents in ammonia solu- 

 tions, by being insoluble in potassium 

 cyanide. 



Nessler's reagent for ammonium salts 

 is an alkaline solution of mercuric chlo- 

 ride and potassium iodide. With am- 

 monia as well as with ammonium salts it 

 causes a yellow to reddish-brown colora- 

 tion or precipitate. The reagent is pre- 

 pared according to various formulae, of 

 which the following are typical; 



I. 50 g. potassium iodide are dis- 

 solved in 50 cc. hot water and concen- 

 trated mercuric chloride solution (20-25 

 g. mercuric chloride) added until a per- 

 manent precipitate appears. After filter- 

 ing 150 g. potassium hydroxide dissolved 

 in 300 ccs. water are added, and the 

 whole diluted to one liter. 5 cc. more of 

 the mercuric chloride solution is now 

 added, the resulting precipitate allowed 

 to settle, and the clear liquid decanted 

 {Kubel). 



II. Dissolve 2 g, potassium iodide in 

 5 g. water; add 4 g. of mercuric chloride, 

 or enough so that upon warming, a little 

 of the precipitate remains undissolved. 

 After cooling, dilute with 20 g. water, 

 filter, and add 30 ccs. of a solution of 1 

 p. KOH in 2 p. of water. {Ludwig 

 Medicin. Chemie.) 



Nessler's reagent for wine pigments is 

 a solution of 7 p. alum and 10 p. sodium 

 acetate in 100 p. water. 



Neubauer's test for biliary acids is a 

 modification of Pettenkofer' s reaction. 

 A few drops of urine are evaporated to 

 dryness on the water-bath, a drop of 



sugar solution (1:500) and a drop of con- 

 centrated sulphuric acid are added, and 

 the whole heated on the water-bath. If 

 biliary acids are present, a violet-red 

 color appears at the edge. 



Neubauer's test for chloroform in the 

 urine. A current of air is passed first 

 through the urine in question, then 

 through a red-hot porcelain tube, and 

 finally through a solution of silver nitrate. 

 If chloroform was present in the urine, a 

 precipitate of silver chloride is formed. 



Neumann-Wender's alkaloid reagent 

 is furfurol-sulphuric acid (5 drops of fur- 

 furol in 10 ccs. pure concentrated sul- 

 phuric acid). See Weppen's veratrin 

 reaction. 



Neumann=Wender's test for grape 

 sugar in the urine. 1 cc. of diluted 

 urine (1 p. urine to 10 p. water) is treated 

 with 1 cc, each of methylene blue solu- 

 tion (1:1000) and normal KOH solution 

 and hoiled for a minute. If the solution 

 is hereby completely decolorized, sugar 

 was present in the urine. Compare 

 Mulder's test. 



Nickel's test for mineral acids in the 

 presence of organic acids depends upon 

 the fact that only the presence of the 

 former is wood stained by phloroglucin. 

 If 0.5 p. c. of hydrochloric acid is present 

 in vinegar, upon adding phloroglucin 

 and a piece of pine wood or wood pulp 

 paper, this latter is distinctly stained 

 upon boiling the solution. 



Nickel's color reactions of carbon com- 

 pounds. Compare Zeitsch. f. analy. 

 Chem. 1889, p. 244, also see under Mil- 

 Ion's reagent. 



Niviere and Hubert's test for fluorine 

 in wine. Render the wine slightly alka- 

 line with ammonium carbonate and, by 

 means of calcium chloride, precipitate 



