108 



five, represents the amount of Hydrocyanic acid. — Or, the result- 

 ing filtered solution of nitrate of silver is mixed \rith hydrochloric 

 acid, the deposit collected, washed, dried, and weighed. Thi.s 

 weight, divided by 5.35, also gives the quantity of H. acid. 



Volumetrically, the same object of estimation is completed with 

 greater expedition and unaffected by the presence or absence of 

 hydrochloric or formic acids. For this purpose, dissolve 3 '15 

 grammes of fused nitrate of silver in water, until the whole 

 amounts to 100 cubic centimeters. On the other hand, add to the 

 distillate in question, or to a certain fraction of it, potash-ley in 

 excess, then a few drops of chloride of sodium solution, and at last 

 cautiously, and under continual stirring, just enough of the nitrate 

 of silver solution to obtain a slight precipitate, which does not re- 

 dissolve. Every cubic centimeter of the silver solution, used for 

 this purpose, indicates 0*01 gramme Hydrocyanic acid. 



To compu^te from the quantity of H. acid the amoi;nt of 

 amygdalin, originally present, the following equation will serve as 

 a guide: — One equivalent AmygdalinnCio H27 NO22 + 4 HO is 

 equal to 1 eq. Hydrocyanic acid = HC 2 N -|- 2 eq. Grape-sugar= 

 2 C12 H12 O12 + 1 eq. Oil of bitter almonds izCu He O2. It 

 follows herefrom, that by multiplying the weight of the Hydro- 

 cyanic acid with 17, we obtain the weight of the amygdalin as 

 required. 



Hytrin. Alkaloid, besides cocain (see this), in the coca-leaves. 

 When, ia the preparation of cocain, more of the soda is added to 

 the slightly alkaline liquid, from which the cocain has been 

 removed by means of ether, Hygrin and a neutral oil of tobacco- 

 odour are dissolved by once more shaking with ether, and remain 

 behind after the ether has been distilled off. By heating this 

 residue to the boiling point, the temperature rises quickly to 280°, 

 a brown alkaline oil passes over and a black resin remains. The 

 distillate when kept at 140° for several hours in a current of 

 hydrogen gas, allows the greater part (a) of a yellow colour to 

 pass over, the rest being only volatilized at 140° to 230°, and 

 condensing to a thick brown oil (b). Both portions contain 

 Hygrin, but contaminated in b with a neutral oil, and in a with 

 other volatile substances. To remove any ammonia present, a is 

 converted into the oxalate and dissolved in absolute alcohol, the 

 liquid is evaporated, and the remnant is mixed with potash-ley, 

 which separates the H. as an oü. After heating this alkaline 

 solution to the boiling-point in a current of hydi'ogen gas, 

 Hygrin, dissolved in water, passes over. It is separated from the 

 distillate by ether and remains after the ether has been distilled 

 off. The nevitral oil, present besides Hygrin in b, is removed by 

 dissolving b in water acidulated with hydi'ochloric acid, shaking 

 with ether and decanting the ethereous liqu.id; the solution, 



