JUSTUS VON LIEBIG. 265 
just as little the value of an acquaintance with the peculiarities of dif- 
ferent solvents. Consider only an extract of a plant or of flesh which 
contains half a dozen crystalline bodies in very small quantities embed - 
ded in extraneous matter, which almost entirely masks the properties 
of the others; and yet, in this magma, we can recognize by means of 
chemical reactions the peculiarities of every single body in the mixed 
mass, and learn to distinguish what is a product of decomposition and 
what is not, in order to be able to separate them afterwards by means 
which will exert no decomposing influence. An example of the great 
ditficulty of finding the right way in such researches is afforded by the 
analysis of bile by Berzelius. Of all the numerous substances which 
he has described as its constituents no one is, properly speaking, con- 
tained in the natural bile. 
An extremely short time had been sufficient for the famous pupils of 
the Swedish master to give a wonderful degree of perfection to mineral 
analysis which depends on an accurate knowledge of the properties of 
inorganic bodies; their compounds and their behavior to each other 
were studied in all directions by the Swedish school with a keenness 
quite unusual previously and even now unsurpassed. Physical chem- 
istry, which investigates the uniform relations between physical prop- 
erties and chemical composition, had already gained a firm foundation 
by the discoveries of Gay-Lussae and von Humboldt, on the combining 
proportions of bodies in the gaseous state, and those of Mitscherlich, 
on the relations between crystalline form and chemical composition; 
and in chemical proportions the structure appeared to have received its 
coping-stones and to stand forth completed. All that foreign countries 
had acquired in bygone times in the way of discoveries now yielded 
rich fruit also in Germany. 
Organic chemistry—or what is now called organic chemistry—had then 
no existence. It is true that Thenard and Gay-Lussac, Berzelius, 
Prout, and Débereiner had already laid the foundations of organic 
analysis, but even the great investigations of Chevreul upon the fatty 
bodies excited but little attention for many years. Inorganic chemistry 
demanded too much attention, and, in fact, monopolized the best ener- 
gies. 
The bent which I aequired in Paris was in a quite different direction. 
Through the work which Gay-Lussac had done with me upon fulmi- 
nating silver I was familiar with organic analysis, and I very soon saw 
that all progress in organic chemistry depended essentially upon its 
simplification; for in this branch of chemistry one has to do not 
with different elements which can be recognized by their peculiar prop- 
erties, but always with the same elements whose relative proportions 
and arrangement determine the properties of organic compounds. 
In organic chemistry an analysis is necessary to do that for which a 
reaction suffices in inorganic chemistry. 
