122 FINE CHEMICALS AND PHARMACEUTICS. [ I V. 



calcium or cyanide of potassium, and botli must be sur- 

 rounded witli water of 86° F. By enclosing the condenser 

 in a mixture of ice and salt, the acid is made to crystallize. 



Gallic Acid. — This acid may be made by boiling tannin 

 with dilute sulphuric acid, until the liquid crystallizes on- cool- 

 ing. Wetherill (Journ. Pharm. xii. 107) gives 1 pt. sulphuric 

 acid (1.84) to 4 pts. water, as the proper strength of the acid ; 

 and 500 cubic centimetres of this mixture to 50 grm. dry tan- 

 nin, as the best proportions. The product will be upwards of 

 40 grm. gallic acid. 



Succinic Acid. — Wackenroder has found that much of the 

 commercial acid is adulterated largely with tartaric acid, 

 drenched with oil of amber. (Archiv. d. Pharm. 1. 280.) 



Qliloroform. — Soubeiran (Comptes Rendus, 1847) proposes 

 to prepare pure chloroform for medicinal purposes, by the 

 following process. 10 pts. of the best chloride of lime are 

 mixed with 60 pts. water, well stirred and transferred to a 

 copper still of at least one-third greater capacity than the 

 volume of liquid, adding 2 pts. alcohol of 0.85. The apparatus 

 being luted tightly is heated by a brisk fire. As soon as 

 the mixture reaches 176° a violent intumescence ensues, when 

 the fire must be immediately removed, to prevent the liquid 

 from running over iq|o the receiver. This mishap being 

 guarded against by careful management of the heat, the dis- 

 tillate commences to pass over and continues rapidly. When 

 the action becomes slow, the fire must be restirred in order to 

 hasten it. When the distillate ceases to taste sweet, the pro- 

 cess is terminated. The distillate consists of two strata, one 

 dense and yellowish, consisting of chloroform contaminated 

 with alcohol and chlorine ; the other is a mixture of water, 

 alcohol, and chloroform, and, after a day, deposits a portion of 

 the latter product. The chloroform is to be decanted, washed 

 by agitation with water, the chlorine removed by a dilute so- 

 lution of carbonate of soda, and then rectified over chloride 

 of calcium in a water-bath. As the operation is more pro- 

 ductive the quicker it is efiected, the pulverized chloride of 

 lime should be mixed with hot water. 



