CONSTITUENTS OP PLA.NTS, ETC. 319 



culiar strong smell comes from creosote, wood-naphtha, and 

 other bodies. The same smell we have in smoke, and from 

 the presence of the same substances. It is the creosote 

 which makes smoke so irritating to the eyes. It is this 

 substance which, both in smoke and in pyroligneous acid, 

 acts upon meat as an antiseptic. Creosote is a liquid of an 

 oily consistency, and colorless when freshly prepared, but it 

 gradually becomes brown by age. It is a very powerful 

 substance when obtained pure, and is an irritating poison. 

 If taken into the mouth it has a very burning taste, and de- 

 stroys the tender membrane which lines the tongue and 

 mouth. Great care, therefore, should be exercised when it 

 is employed, as it often is, as a remedy for the toothache. 



437. Wood-Naphtha. The liquid portion of the products 

 of the distillation of wood contains, besides acetic acid and 

 creosote, eight or ten other substances; one of these, wood- 

 naphtha, is of considerable importance. It is a volatile, 

 odorous, mobile liquid, resembling alcohol, and yet having 

 a different composition. If it be purified by treatment 

 with lime to remove acetic acid, etc., and then by distilla- 

 tion, a pure substance is obtained, known as methylic alco- 

 hol. This is the first of a series of bodies called alcohols, 

 with one member of which you are familiar, viz., common 

 alcohol. Its composition is CH 3 HO, while common or 

 ethylic alcohol is C 2 H 5 HO. Methylic alcohol burns with 

 a flame much like that of common alcohol, is a good solvent 

 of resinous substances, and, being cheaper than ethylic alco- 

 hol, is of great nse in the arts. 



438. Wood-Tar. This is a resinous substance, and is 

 therefore soluble in alcohol, but not in water. If it be dis- 

 tilled, a volatile oil passes over, called oil of tar, and there 

 is left behind a black pitch. This separation takes place 

 gradually when wood is besmeared with tar, the volatile 

 oil flying off into the air, and the pitch becoming, there- 



