SALICIN. 869 



substance to which Fremy has applied the name peruvine. This 

 last is an oily colourless liquid lighter than water ; its composi- 

 tion is expressed by C 18 H 12 O 2 . Fremy finds the balsam of 

 Tolu to contain the same bodies as the balsam of Peru. Ac- 

 cording to Richter the balsam of Peru contains two different 

 oils, one of which is soluble in alcohol of 75 per cent and is 

 called by him myriospermine, the other oil which is insoluble he 

 names myroociline. On treating the first with an alcoholic solu- 

 tion of potash, an acid is formed different in its capacity of 

 saturation, according to Richter, from cinnamic acid, and which 

 he names myriospermic acid. Its atomic weight deduced from 

 the salt of silver is 1553.85. 



CHAPTER VI. 



SALICIN AND BODIES OBTAINED FROM ITS DECOMPOSITION. 



SECTION I. 



SALICIN. 



Formula : C 42 H 29 O 22 =C 42 H 23 O 16 + 6HO ? (Mulder). 



This neutral crystallizable substance was discovered by 

 Buchner and Leroux in the bark of the Salios helix. It is con- 

 tained in the bark and leaves of all the species of willow which 

 have a bitter taste, and in some poplars. To prepare salicin 

 the fresh bark or dry ground bark is boiled with water till a 

 strong decoction is made ; to the concentrated and boiling decoc- 

 tion oxide of lead is gradually added till the liquid is colourless. 

 Gum, tannin and all extractive matters which may interfere with 

 the crystallization of the salicin are thus carried down by the 

 oxide of lead. The oxide of lead dissolved is then removed first 

 by means of sulphuric acid, and then by sulphuret of barium. 

 The liquid is crystallized by evaporation and the salicin made 

 perfectly white by the use of charcoal and repeated crystalliza- 

 tions. The sulphuret of lead which is precipitated in the 



