APPENDIX. 419 



i volume of this acid mixture to 4 volumes of 95 per cent alcohol. 

 It is preferable that the acid mixture be prepared in advance and 

 allowed to stand until yellow in color before adding it to the alcohol. 



Hopkins-Cole Reagent. 1 To one liter of a saturated solution 

 of oxalic acid add 60 grams of sodium amalgam and allow the 

 mixture to stand until the evolution of gas ceases. Filter and 

 dilute with 2-3 volumes of water. 



Hypobromite Solution. 2 The ingredients of this solution 

 should be prepared in the form of tzvo separate solutions which may 

 be united as needed. 



(a) Dissolve 125 grams of sodium bromide in water, add 125 

 grams of bromine and make the total volume of the solution i 

 liter. 



(b) A solution of sodium hydroxide having a specific gravity of 

 1.25. This is approximately a 22.5 per cent solution. 



Preserve both solutions in rubber-stoppered bottles and when 

 needed for use mix equal volumes of solution a, solution b f and 

 water. 



Iodine Solution. 3 Prepare a 2 per cent solution of potassium 

 iodide and add sufficient iodine to color it a deep yellow. 



Jolles' Reagent. 4 This reagent has the following composition : 



Succinic acid 40 grams. 



Mercuric chloride 20 grams. 



Sodium chloride 20 grams. 



Distilled water 1000 grams. 



Kraut's Reagent. 5 Dissolve 272 grams of potassium iodide 

 in water and add 80 grams of bismuth subnitrate dissolved in 200 

 grams of nitric acid (sp. gr. 1.18). Permit the potassium nitrate 

 to crystallize out, then filter it off and make the filtrate up to i 

 liter with water. 



Lugol's Solution. 6 Dissolve 4 grams of iodine and 6 grams of 

 potassium iodide in 100 c.c. of distilled water. 



Magnesia Mixture. 7 Dissolve 175 grams of magnesium sul- 

 phate and 350 grams of ammonium chloride in 1400 c.c. of distilled 



1 Hopkins-Cole reaction, page 91. 



2 Methods for determination of urea, page 374. 



3 Iodine test, page 44. 



* Jolles' reaction, pages 98 and 316. 

 5 Rosenheim's bismuth test for choline, page 252. 

 8 Gunning's iodoform test, page 328, and Bardach's reaction, page 94. 

 ' Sodium hydroxide and potassium nitrate fusion method for determination 

 of total phosphorus, page 390. 



