42 SCIENTIFIC AND APPLIED PHARMACOGNOSY 



alcohol and various volatile empyreumatic substances. On dis- 

 tillation four distinct classes of products are obtained: (1) An 

 aqueous distillate, from 10 to 20 per cent, consisting chiefly of acetic 

 acid, methyl alcohol and acetone. (2) A light oily distillate, from 

 10 to 15 per cent, coming over under 150 C., and consisting of mesit, 

 toluene, xylene, cumene, methene and eupion, which products are 

 used as solvents for varnishes and similar substances. (3) A heavy 

 oily distillate, about 15 per cent, distilling over between 150 and 250 

 C., and consisting of the creosote oils, viz. : phenol, cresol, creosote, 

 paraffin, naphthalene, pyrene, chrysene, retene and some other sub- 

 stances. (4) A black resinous mass, called pitch (50 to 65 per cent) 

 which has the odor of tar and is still official in some pharma- 

 copoeias. 



In the distillation of pine wood tar the distillate, which is lighter 

 than water, contains a volatile oil known as oil of tar (Oleum Picis 

 Liquidae). When recently prepared it is colorless, but it gradually 

 darkens, becoming finally dark reddish-brown, there separating at the 

 same time a blackish, resinous substance. Oil of tar consists chiefly 

 of oil of turpentine, with some of the lighter hydrocarbons and phenol 

 compounds, acetic and other acids, and a number of empyreumatic 

 products. 



Allied Products. Beech-wood tar is the product of the destructive 

 distillation of the wood of Fagus sylvatica and F. ferruginea (Fam, 

 Fagacese). It is distinguished from pine tar by the petroleum ether 

 extract not giving a green color with copper acetate solution, and in 

 the creosote oils containing a considerable amount of guaiacol. The 

 official creosote is a mixture of guaiacol and creosol with some other 

 phenol derivatives, as xylenol, methyl creosol and methyl guaiacol, 

 obtained from the heavy oily distillate of beech-wood tar. Guaiacol 

 is of interest because on treatment with chemicals it may be con- 

 verted into vanillin. 



TEREBINTHINA LARICINA (Terebinthina Veneta.) Larch Tur- 

 pentine or Venice Turpentine. An oleo-resin obtained from the Euro- 

 pean larch, Larix decidua (Fam. Pinacese). The tree is indigenous to 

 the Alps and Carpathian Mountains and is extensively cultivated. 

 The oleo-resin is obtained by making incisions into the heart wood 

 in the spring of the year and these are then plugged until the fall, 

 when the plug is removed and the viscid liquid is collected by means of 

 a spoon. From each incision about 250 c.c. of oleo-resin is obtained 

 annually. The yield from each tree is limited, as the oleo-resin is 

 only secreted for a few years. The commercial supplies are obtained 

 mostly from the Southern Tyrol. 



