PIX LIQUIDA 610 



Maly is of opinion that the same amorphous resin occurs in all the 

 Coniferce, and that it yields by hydration the same acid, namely Ahietic, 

 which has been described by fonner chemists as Pinic, Silvic, and 

 Pimaric acids, all of which indeed are admitted to have the same com- 

 position. We must however remember that several sorts of turpentine, 

 as Canada Balsam, appear incapable, according to our experiments, of 

 yielding any crystalline resinoid compound whatever ; and that their 

 amorphous resin being but partially soluble is certainly not a homo- 

 geneous substance. 



The crystals as formed naturally in the common turpentines do not 

 exhibit precisely the same forms as those obtained artificially when the 

 resins are agitated with warm diluted alcohol, as in the preparation of 

 abietic acid. As to Pimaric Acid, we have prepared it in quantity 

 from galijwt, the resin oi Pinv^s Pinaster, but have always found its 

 crystalline character entirely different from that of abietic acid.^ 



We are inclined, therefore, to think that the composition of the 

 resins oi Coniferce is not so uniform as Maly suggests. The remarkable 

 variety of their essential oils is a fact which seems in favour of our 

 view. 



Uses — Burgundy pitch is prescribed as an ingredient of plastere, 

 and thus employed is useful as a mild stimulant. In Germany it has 

 some economic applications, one of which is the lining of beer casks, 

 for which purpose a composition is used called Brauerpech (brewers' 

 pitch), made by mixing it with colophony or galipot. 



Adulteration — No drug Is the subject of more adulteration than 

 Burgundy pitch, so much so that the very name is understood by some 

 pharmacologists to be that of a manufactured compound. The substance 

 commonly sold in England is made by melting together colophony 

 with palm oil or some other fat, water being stirred in to render the 

 mixture opaque. In appearance it is very variable, different samples 

 presenting different shades of bright or dull yellow or yeUowish-brown. 

 Many when broken exhibit numerous cavities containing air or water ; 

 all are more or less opaque, becoming in time transparent on the surface 

 by the loss of water. Artificial Burgundy pitch is offered for sale in 

 bladders; it has a weak terebinth inous odour, and is devoid of the 

 peculiar fragrance of the genuine. The presence of a fatty oil is easily 

 discovered by treatment with double its weight of glacial acetic acid, 

 which forms a turbid mixture, separating by repose into two layers, the 

 upper being oily. 



PIX LIQUIDA. 



Wood Tar; F. Govdron vegetal, Poix liquids; G. Holztheer, 

 Fichtentheer. 



Botanical Origin — Tar is obtained by submitting the wood of the 

 stems and roots of coniferous trees to dry or destructive distillation. 

 That found in commerce is produced in Northern Europe, chiefly from 

 two species, namely Pinus silvestris L. and P. Ledebourii Endl. {Larix 

 sihii'ica Ledeb.). These trees constitute the vast forests of Arctic 

 Europe and Asia. 



^ Jahresbericht of Wiggera and Husemanu for 1867. 37. 



