INTRODUCTION. 5 



in its progress dependent on tho latter: in fact, it is only a special 

 branch of the same. 



Although in the infancy of chemical study a certain amount of notice 

 had been taken of organic bodies, nevertheless, owing to the nature of the 

 matter to be considered, they could only be dealt with (scientifically 

 speaking) subsequently to the establishment of laws relative to inorganic 

 substances and their combinations. And only after the latter, as the 

 simpler had been studied, and that the more important laws of inorganic 

 chemistry had been laid down, did it become possible to invade the more 

 obscure field of organic chemistry with success. 



It must be admitted, however, that important discoveries had been 

 made by Sclieele (1742-1786) in the latter subject. Thus a number of 

 vegetable acids, glycerin, uric acid, and cyanic acid, had all been brought 

 to light. But these were only details, whose worth from a scientific point 

 of view it remained for a later day to demonstrate. It was only with 

 the introduction of quantitative analysis by Lavoisier (1743-1794), and 

 after that his contemporary, Priestley (1733-1804), had: discovered oxy- 

 gen, that a new era in chemical science began to dawn an epoch of exact 

 research supervening upon the overthrow of phlogistic theory. From 

 this point on it became possible to gain an insight into chemical com- 

 bination by means of the balance to recognise the elements of organic 

 bodies, to place upon a sound basis the rules of equivalent and atomic 

 weight, and establish a foundation for a system of stochiometry. 



And as in microscopical anatomy the improvement of instruments led 

 within a short space of time to a more extended acquaintance with the 

 subject, so do we see here in the province of chemistry the dawn of an era 

 under the sun of Lavoisier's genius, in which, by a rapid succession of 

 discoveries, the new science attained, within a short space of time, a 

 wonderful degree of development and cxtensiveness. 



It would be impossible, in the scope of such a work as the present, to 

 bring in review the details of this progress in development, and we shall 

 only mention a few points in regard to it of special interest. 



The first impulse was given to the study of organic substances through 

 the works of Vauquetin (1763-1829) and Foucroy (1755-1809). Much 

 profit accrued also to zoochemistry through their labours in the investiga- 

 tion of the constituents of the urine, which were also ably handled by 

 Proust (1755-1826). In the year 1815 Gay-Lussac (1788-1852) dis- 

 covered cyanogen, an organic compound which conducts itself in com- 

 bination much in the same way as an organic element. Thus he paved 

 the way for the theory of organic radicals, to be further developed at the 

 hands of future observers. Many other discoveries, both in organic and 

 animal chemistry, were made about the same time by Thenard (1777-1857), 

 and in 1823 Clievreul published his celebrated treatise on animal fats. 

 Modern elementary analysis (brought to such a degree of perfection at a 

 later date) was first opened up by Gay-Lussac and Thenard, and from 

 that time on a knowledge of organic bodies, from a quantitative point of 

 view, was rendered possible. 



But under Berzelius (1779-1848), the greatest chemist of his time, the 

 whole science now made the most brilliant advance, especially in the 

 direction of organic analysis, which was pursued by him with all the 

 accuracy of the present day. He was, in fact, the founder of the stochi- 

 ometry of organic bodies, and of the definite systematised zoochemistry wo 

 at present possess. Then the name of Mitscherlich (born 1796) must be 



