309 
of Edinburgh , Session 1873-74. 
ments) we still employ, made it easy for any advanced student to 
make an accurate analysis of an organic body. It may be truly 
said that the astonishingly rapid development of organic chemistry, 
which dates from that time, was only rendered possible by the 
simplification of the method of organic analysis entirely due to 
Liebig. 
Of Liebig’s discoveries and speculations it is possible to give, 
in such a notice as this, only an outline. The whole progress of 
chemistry for the last fifty years is so intimately connected with 
what he did, that a life of Liebig would necessarily include the 
history of chemistry for that period. 
His investigations extend to nearly every branch of chemistry, 
but it was to organic chemistry that he specially devoted himself ; 
and it is through his work, in this direction chiefly, that he has 
influenced other departments of chemistry and the science gene- 
rally. His first research, that on fulminic acid, published in 
Paris in 1823, led to the recognition of the isomerism of ful- 
minic acid and the cyanic acid discovered in 1822 by Wohler, 
and was followed by a long series of investigations on the com- 
pounds related to cyanogen, in which he opened out and to a 
great extent explored this intricate and interesting path of inquiry. 
Another group of researches was directed to the determination 
of the composition and constitution of organic acids. In a com- 
prehensive memoir published in 1838, he pointed out the analogies 
between many organic acids and phosphoric acid, and introduced 
the idea of polybasic acid into organic chemistry, enumerating the 
criteria for the determination of the basicity of an acid with extra- 
ordinary precision and accuracy. 
He made numerous analyses of the vegetable alkaloids, and 
greatly increased our knowledge of their properties, of their equi- 
valents, and of the relation of equivalent to composition. 
His investigations into the derivatives of alcohol, particularly 
those formed by oxidation and by the action of chlorine, including 
the discovery of aldehyde and chloral, poured a flood of light upon 
the whole question of the constitution of organic compounds. 
Liebig was the first to regard ether as an oxide, of which alcohol is 
the hydrate, and the compound ethers salts. By doing so he chal- 
lenged the defenders of the “etherine” theory, who looked upon 
