“ 
Gerhardi’s Organic Chemisiry. is 
Arr. XII—Review of the Organic Chemisiry of M. Cuartes 
GeRHARDT.* 
Tu1s book appeals with peculiar claims to the notice of all 
interested in the progress of chemical science. Organic chemis- 
try has made great progress during the last few years ; but until 
the publication of the Précis, with the exception of Liebig’s ex- 
cellent Traité de Chimie Organique, no systematic work embra- 
cing the results of the last decade had appeared. This is to be 
ascribed to the great difficulty of classifying the immense array 
of facts, and harmonizing the various conflicting theories—a task 
indispensable as a preparation for such a work and at the same 
time exceedingly delicate. 
Liebig in his Traité assumed as the basis of his system, the 
theory of compound radicals, and commences with the asser- 
tion, that “organic chemistry is the chemistry of compound radi- 
cals.” This was a most ingenious application of the electro- 
chemical philosophy of Berzelius to the investigation of this class 
of compounds, and was supported by so many analogies as to 
render it very probable; at the same time it admitted the appli- 
cation of the received nomenclature to these bodies. These rad- 
ieals are generally however purely hypothetical, and when we 
are able to isolate substances having the composition assigned to 
them, they are found to possess none of the properties which 
theory would require. Recent experiments have shown that 
mellon and mellonids have not the composition ascribed to them 
by Liebig, and that mellon cannot be regarded as a compound 
radical. Cyanogen and kakodyle must however be excepted, as 
compounds which comport themselves in many respects like ele- 
mentary bodies. Bs 
-'The progress of discovery has shown, that this hypothesis is 
but poorly adapted to form the basis of a system of classification, 
for the discovery of nearly every new body requires the assump- 
tion of an imaginary compound to explain its reactions 10 accord- 
ance with the theory of radicals; and so uncertain are the princi- 
ples which are to direct us in the application of this theory, that 
different chemists often assign very different rational formulas 
arrangement of the ele- 
ments in aleohol; each author seeking by his own to explain 
Dumas regards it as the bi-hy- 
us 
drate of olefiant gas; Liebig as the hydrated protoxyd of ethyle, 
Be cia eek oP a ee 
Cc 
Faculté des Sciences de Montpellier. 2 vols. Svo. 
Cie.) 1845.— We are indebted for this review and abstract o 
