45 
The superabundance of experimental genius in the chemical camp 
must account for the fact that the border-lands between chemistry 
proper and the collateral sciences of physics, physiology, &c., have 
been cultivated chiefly by men who called themselves chemists. It 
is there that Bunsen, Graham, Kopp, Liebig, Begnault, gathered 
part of their laurels. If it were possible to characterise Wohler by 
one stroke of the pen, we should say that of such border-land work 
he did very little — all his work lies in the very core of the science ; 
but on this only relatively narrow field he simply ranks with Scheele, 
no other name, except perhaps that of Berzelius, could fitly be 
placed alongside of these two. 
To begin with Wohler’s minor contributions, and at the same 
time qualify what we have just said of him in a negative sense, let 
us state that Wohler, while a student of medicine in Heidelberg, 
published a thesis on the excretion of substances by the kidneys, 
for which a prize was awarded to him by the Medical Faculty of that 
University in 1823. Mauy years later he resumed this subject 
conjointly with Frerichs; the memoir is in the Annalen dev Chemie 
for 1848 (vol. lxv. p. 325). In this connection we may state that 
we owe to Wohler the best method for the detection of arsenic and 
other mineral poisons in complex organic mixtures. It is described 
shortly in his Mineral Analyse in Beispielen. (The original memoir 
is in the Annalen , for 1849, vol. lxix. p. 364.) 
We have not been able to find out exactly what Wohler did 
while in Berzelius’s laboratory, and presume that, as a sensible man, 
he there mainly confined himself to learning the great master’s 
methods. Nothing but a short notice on “Improvements in the 
Preparation of Potassium,” dates from the Stockholm period. It 
is significant, however, as forming the small beginning of. a brilliant 
series of researches on the isolation of elementary substances and their 
properties, a subject for which he evidently had a great love, as he 
always comes back to it in the intervals of other work. In 1827 lie* 
for the first time, succeeded in isolating aluminium, the metal of clay, 
by means of a method which was soon found to be more generally ap- 
plicable. Alumina, like many other metallic oxides, is not reducible 
by electrolysis or by the action of charcoal at any temperature. But, 
when heated with charcoal in chlorine gas, it passes into the state of a 
volatile chloride. What Wohler found was that this chloride when 
