112 TRANSACTIONS OF THE [maR. 21, 
of estimating them, and, together with his pupils Will and Varren- 
trapp, invented the methods of analysis which we practise to-day. 
In 1832 Liebig and Wohler discovered the radical or parent sub- 
stance of benzoie acid. They also noted that oil of bitter almonds 
could be oxidized and gave benzoic acid. It followed, therefore, 
that there must be some connection between benzoic acid and the 
oil of bitter almonds. It had been previously ascertained that 
benzoic acid could be obtained from aromatic gum benzoin. Then 
Mitscherlich, another chemist, found that by heating benzoic acid 
with lime he obtained benzol, a liquid hydrocarbon ; therefore there 
must be some connection between this hydrocarbon and oil of bitter 
almonds, for the oil gives benzoic acid and benzoic acid gives benzol. 
Further, Mitscherlich converted benzol into benzoic acid again by 
oxidation. It was ultimately ascertained that oil of bitter almonds 
is an intermediate product between benzol and benzoic acid; and 
when Hoffmann discovered benzol in coal-tar in the year 1845 a 
source for making it artificially was obtained. 
But to return to the vital-foree theory. 
In 1835 or 1836, Berthelot, the Frenchman, succeeded in uniting 
carbon and hydrogen and produced the hy drocarbon called acety- 
lene, consisting of two atoms of carbon united to two atoms of 
hydrogen. This was accomplished by using a powerful electric 
battery, and allowing the sparks to pass between two carbon poles 
in an atmosphere of. hydrogen gas. Here was an actual union of 
the very elements themselves to produce a compound characteristic 
of organic substances, a hydrocarbon that up to that time had only 
been obtained by decomposing organic compounds, such as ear- 
bonized tartar and water, wood-alcohol, and ether, by passing the 
vapors through red-hot tubes. 
From this gas acetylene, the hydrocarbon ethene, or olefiant gas, 
was made by acting on it with nascent hydrogen. By absorbing 
olefiant gas in sulphuric acid a compound is formed which was 
called sulphovinie acid, or ethyl acid sulphate. When this is boiled 
with water we get ethyl hydroxide or alcohol and sulphuric acid. 
From this series of steps it is evident that, starting from the ele- 
ments themselves, we are able to build up compounds that are 
entirely characteristic of organic substances, and this without the 
intervention of any vital force. This sounds rather complicated, 
but is only so in words. The process is simple. 
It was in the efforts to obtain knowledge of the active principles 
of animal and vegetable substances used in medicines that many of 
the greatest discoveries in organic chemistry were made. 
In 1808, Derosne, in Paris, discovered morphine and narcotine in 
opium, and called the mixture a salt of opium. He also knew it 
was a base like ammonia. 
Sertiirner, a German apothecary, in 1806, discovered that mor- 
phine existed in opium combined with an acid, called meconie acid. 
This discovery started the search for alkaloids in plants, as up to 
