MM. Strecker and Moller on Vulpic Acid. 211 
Berthelot also examined the action of organic acids at a high 
temperature on orcine, thymole, alizarine, and the hydrates of 
oil of turpentine. All these substances, with the exception of 
orcine, contain 20 equivs. of carbon. Orcine, C!* H® 04, appears 
to form a compound with stearic acid. The experiments with 
the other substances led to no positive results. 
Vulpic acid, one of the lichen acids first isolated, and found in 
the Cetraria vulpina, was so little known that its identity as a 
distinct acid was doubted. Moller and Strecker* have recently 
investigated it, and have arrived at some very interesting results. 
The acid is prepared by macerating the lichen with lukewarm 
water containing milk of lime, and supersaturating the extract 
with hydrochloric acid; a precipitate is formed which is washed 
with cold water and dissolved in boiling alcohol. On cooling, the 
acid crystallizes in tolerably long needles of the monoclinic system, 
which in colour and lustre resemble sulphur. Its best solvent 
is chloroform, by which it may be directly extracted from the 
lichen. Its formula is C3*H'!*0!°, and it is monobasic. It 
forms crystallized salts with potash, ammonia, lime, and baryta. 
The salts of the heavier metals are obtained by the double de- 
composition of vulpate of potash with the corresponding metallic 
solutions. In appearance vulpic acid most resembles. usnic acid ; 
and their composition only differs by the elements of water, the 
formula of usnic acid being C®* H!®O*; but in their chemical 
deportments there is considerable divergence. 
When vulpic acid is boiled in a distillation apparatus with 
baryta water, oxalate of baryta is gradually deposited, and a 
liquid distils over with the water, which is methylic alcohol. In 
the residual liquor from which the oxalate has precipitated, the 
soluble baryta-salt of a new acid is contained. It is obtained 
thus: the excess of baryta is removed by carbonic acid, the liquor 
filtered, concentrated, and supersaturated with hydrochloric acid. 
A erystalline substance separates, which, when recrystallized from 
alcohol, forms beautiful thin rhombic plates, which melt at 76°°5 
and distil at 265°. This substance is strongly acid; it forms 
salts with alkalies and alkaline earths, which, however, from their 
great solubility, are difficult to crystallize. 
The composition of the acid is C'®H®O*, which is that of 
the toluylic acid obtained by Noad by oxidizing cymole by nitric 
acid. But the two substances are only isomeric, and not iden- 
tical; for Noad’s acid crystallizes in needles, and melts above 100°. 
This new acid, which has been named alphatoluylie acid, agrees 
closely in its properties with the toluylic acid obtained by Can- 
nizaro by boiling cyanide of benzyle with potash. 
* Liebig’s Annalen, January 1860. 
