APPENDIX I. 251 



Magnesium Sulphate, cold ; saturated solution. 



Mercuric Chloride, 1 : 20. 



Millon's Reagent. Warm one part of mercury with two 

 parts of nitric acid, specific gravity 1.4, until the mer- 

 cury is completely dissolved. Dilute one volume of 

 the solution with two volumes of water. 



0. Nasse (Arch. f. d. ges. Physiol. 83, 361 (1901) ) rec- 

 ommends an aqueous solution of mercuric acetate, to 

 which, just before using, a few drops of a 1 per cent, po- 

 tassium nitrite solution are to be added and also, in case 

 the reaction is not distinctly acid, a little dilute acetic acid. 



Nessler's Reagent. Dissolve 50 g. of potassium iodide in the 

 same quantity of water, then heat and add a hot, concen- 

 trated mercuric chloride solution until some mercuric 

 iodide remains undissolved. (Twenty to twenty-five 

 grams of HgCl 2 are required.) Filter and add 150 g. of 

 potassium hydroxide dissolved in 300 g. of water, then 

 dilute to one liter, add 5 cc. more of the mercuric chlo- 

 ride solution, let the precipitate settle and decant. The 

 solution is kept in small closed bottles. It must be 

 completely saturated with mercuric iodide, otherwise 

 the reagent is not very sensitive. 



Nitric Acid. Must be free from hydrochloric acid and color- 

 less, and free from nitrous acid, specific gravity 1.2. 



Nylander's Solution. One hundred grams of caustic soda 

 solution of 1.119 specific gravity (10.33 g. NaOH), 4 g. of 

 potassium sodium tartrate, and 2 g. of bismuth subnitrate. 



Oxidizing Mixture. Three parts of KN0 3 and one part of 

 Na 2 C0 3 , dry and pure. 



Phosphotungstic Acid, 1 : 20, acidified with hydrochloric acid. 



Platinum Chloride. Must dissolve and give a clear solution 

 in alcohol, 1 : 10. 



Potassium Chromate. Yellow chromate of potassium, 

 1:20. 



