860 FOODS AND FOOD ADULTERANTS. 



is insoluble. According to him, wax after saponitication yields 50 per cent of matter 

 soluble in glacial acid (myricyl alcohol). In following his directions we have not 

 l>een able to separate the paraffin nor to obtain a constant quantity for the part of 

 the wax soluble in chloroform. 



Our method is to distil off most of the chloroform, transfer the residue to a tared 

 capsule, evaporate, dry at 100, and weigh. A weighed portion of this dried residue 

 is to be transferred to a small flask (with a reflux condenser attached), together with 

 4or5cc of anhydrous acetic acid to etherify the myricyl alcohol, which becomes 

 soluble iu it ou warming, and the whole heated for an hour. After the completion 

 of the reaction the product is transferred to a glass tube marked for 10 cc, and 

 graduated to tenths. .Rinse the flask with a little boiling acid, and add to the pre- 

 ceding. The total volume should be about 9 cc. Close the tube with a cork, place in 

 a water bath kept at 90, and shake till complete emulsification is effected. Let it 

 remain quiet in the bath till it becomes clear again, and then read of the volume of 

 paraffin floating on the surface of the acid. Reenjulsify, allow to become clear, and 

 read, and so on. till the readings give concor lant results. One gram of paraffin equals 

 1.35 to 1.40cc. On deducting the weight of the paraffin from the total weight of 

 the chloroform extract, the residue represents the portion of the wax dissolved in the 

 chloroform (myricyl alcohol). 



(3) Determination of the stearin. The portion of the saponified product insoluble 

 in chloroform is composed of the soaps formed from the stearin and stearic acids, and 

 from the cerotic acid. To determine the first, dissolve this residue in boiling water, 

 filter to separate the silica and asbestos., and decompose the filtrate by a slight excess 

 of dilute nitric acid to set free the fatty acids. Again filter, and in the filtrate titrate 

 the glycerine, after neutralization and precipitation by aceiate of lead, by means of 

 potassic bichromate. Five grams of glycerine are equivalent to 95 grams of stearin. 

 In cases where the percentage of stearin is but slight, it would be preferable to sa- 

 ponify 10 to 25 grams, and determine glycerine iu the product by the bichromate 

 method. 



By the above method can be determined : 



(1) Stearic acid by alkalimetry. 



(2) Paraffin by -volume of matter insoluble in glacial acetic acid. 



(3) Part of the wax by deducting the paraffin from the weight of the residue solu- 

 ble in chloroform. 



(4) Steariue by titrating the glycerin. 



(5) The residual portion of the wax ( cerotic acid) by difference. 



