LECTURE VII. 



ORGANIC CHEMISTRY AT THE COMMENCEMENT OF ITS DEVELOPMENT 

 ATTEMPTS TO DETERMINE THE ELEMENTARY CONSTITUENTS OF 

 ORGANIC COMPOUNDS ISOMERISM AND POLYMERISM VIEWS 

 REGARDING CONSTITUTION RADICAL THEORY. 



IN this lecture I shall endeavour to give an account of the 

 development of organic chemistry. I have intentionally post- 

 poned this subject until now because I wished to consider it in 

 a connected manner, because it had almost no influence during 

 the first three decades of the present century upon the perfect- 

 ing of general theories, and also because the views which 

 constitute the basis of inorganic chemistry did not, at first, 

 seem to be capable of any application to the organic branch of 

 the science. Thus we nd Berzelius, in 1828, treating the 

 subject of the organic compounds separately. The electro- 

 chemical theory, the law of multiple proportions, and the law 

 of volumes did not appear to dominate substances derived from 

 the animal and vegetable kingdoms ; these substances were 

 subject to the so-called vital force, the nature of which was 

 wholly unknown and obscure. It only became possible to 

 extend to organic chemistry also, the laws which held for 

 inorganic substances, after the study of this part of the subject 

 had further attracted thinkers to itself. The opinions and 

 hypotheses to which the examination of the better known 

 substances had led, had now to be turned to account in the 

 younger branch of the science. It was dualism, in particular, 

 which was now introduced into organic chemistry also. 



Lavoisier had already assumed, as has been stated previously, 

 that the acids consist of oxygen and a basis ; and that, in 

 inorganic compounds, the latter is an element, while in organic 



