The composition of organic compounds was at that time not understood, and it was Lavoisier who established the fact that they consisted of carbon, hydrogen, and oxygen, and who made systematic analyses of the substances concerned in fermentation (1784-1789). Lavoisier [1789] applied the results of these analyses to the study of alcoholic fermentation, and by employing the principle which he regarded as the foundation of experimental chemistry, "that there is the same quantity of matter before and after the operation," he drew up an equation between the quantities of carbon, hydrogen, and oxygen in the original sugar and in the resulting substances, alcohol, carbon dioxide, and acetic acid, showing that the products contained the whole matter of the sugar, and thus for the first time giving a clear view of the chemical [p003] change which occurs in fermentation. The conclusion to which he came was, we now know, very nearly accurate, but the research must be regarded as one of those remarkable instances in which the genius of the investigator triumphs over experimental deficiencies, for the analytical numbers employed contained grave errors, and it was only by a fortunate compensation of these that a result so near the truth was attained. Lavoisier's equation or balance sheet was as follows:-- Carbon. Hydrogen. Oxygen. 95·9 pounds of sugar (cane sugar) consist 26·8 7·7 61·4 of These yield:-- 57·7 pounds of alcohol containing 16·7 9·6 31·4 35·3 " carbon dioxide containing 9·9 -- 25·4 2·5 " acetic acid containing 0·6 0·2 1·7 ----- ---- ----- Total contained in products 27·2 9·8 58·5 The true composition of the sugar used was carbon 40·4, hydrogen 6·1, oxygen 49·4. Lavoisier expressed no view as to the agency by which fermentation was brought about, but came to a very definite and characteristic conclusion as to the chemical nature of the change. The sugar, which he regarded in harmony with his general views as an oxide, was split into two parts, one of which was oxidised at the expense of the other to form carbonic acid, whilst the other was deoxygenised in favour of the former to produce the combustible substance alcohol, "so that if it were possible to recombine these two substances, alcohol and carbonic acid, sugar would result". From this point commences the modern study of the problem. Provided by the genius of Lavoisier with the assurance that the hitherto mysterious process of fermentation was to be ranked along with familiar chemical changes, and that it proceeded in harmony with the same quantitative laws as these simpler reactions, chemists were stimulated in their desire to penetrate further into the mysteries of the phenomenon, and the importance and interest of the problem attracted many workers.