110 TRANSACTIONS OF THE [mMaArR. 21, 
workers in chemical science were practitioners of the healing art, 
either as pharmacists or as physicians. Stahl was a physician, 
Boerhaave was a physician, Scheele was an apothecary, Liebig an 
apothecary’s apprentice; and you must also remember that all 
these men worked for the love of the science, and without any idea 
of the utility of their labors. Who can estimate the value of the 
discovery of chloroform and chloral? yet Liebig had no idea of 
making them useful when he discovered them. ‘But this was the 
beginning of a new era in organic chemistry, and discovery followed 
discovery in such rapid succession that the disciples of the vital- 
force theory were obliged to give way to the cloud of witnesses 
taken from experimental chemistry proving the fallacy of their 
theories. 
While Scheele, Bergman and Rouelle, and others were working 
experimentally upon organic substances, Lavoisier, the Frenchman, 
was watching their work, and, in connection with his experiments 
upon oxygen and ¢ombustion, was paving the rough and rocky road 
that led to modern researches. He it was who first proved how few 
of the elements enter into the constitution of organic substances ; 
and, in the year 1793, he points out that while in ‘the mineral king- 
dom a large number of elements enter into the constitution of sub- 
stances, in the animal kingdom we have generally only carbon and 
hydrogen, and sometimes nitrogen and phosphorus. It is rather 
curious to note how near he was to the truth, with his limited 
knowledge of the elementary composition of organic bodies, for 
to-day we say that organic compounds contain, as a rule, only car- 
bon, hydrogen, oxygen, nitrogen, and sulphur. Lavoisier had an 
idea that oxygen was confined to the mineral kingdom, and his 
methods of research had not taken into consideration animal pro- 
du:ts, like albumen, which contain sulphur. Nevertheless, he was 
the first chemist that saw clearly the special functions of carbon in 
the constitution of organic compounds. 
Berzelius improved the methods of ultimate organic analysis, and 
by his indefatigable energy as an analyst made us better acquainted 
with a vast number of chemical compounds and their constituents ; 
but he firmly believed that the essential elements of organic com- 
pounds were carbon, hydrogen, and nitrogen. Then came the dis- 
covery by Gay Lussac of the compound radicle cyanogen, which 
caused quite a flutter in the chemical world; but it was ultimately 
believed that this was really an inorganic rather than an organic 
compound; and Leopold Gmelin, in his great ‘‘ Handbuch” in 1817, 
states that the difference between organic and inorganic bodies con- 
sists in the fact that the inorganic compounds can be prepared arti- 
ficially from their elements, while the organic compounds cannot, 
and about the same time Berzelius enforced the Bee by a 
sentence in the introduction to his ‘ Treatise.” He says: “In 
living nature the elements appear to obey very different laws from 
those in inorganic nature; the products which result from the action 
