LECTURE VII.] HISTORY OF CHEMISTRY. I2Q 



bodies, of alcohols and analogous bodies, these are the real 

 elements with which organic chemistry operates, and not the 

 ultimate elements carbon, hydrogen, oxygen, and nitrogen, which 

 only appear when every trace of organic origin has disappeared." 

 It will thus be understood that the atoms which constituted 

 such a group were supposed to be held together by stronger 

 forces than those which united the group to other atoms. The 

 radical in this way attained a very real significance in the minds 

 of the chemists of that period ; it actually existed in the com- 

 pound, and hence,- in any particular substance, only a single 

 radical could be assumed since there was only one present. 

 And thus, with the constantly increasing importance which the 

 radical of a substance attained in respect to views concerning 

 its constitution, divergences necessarily arose in the choice of a 

 radical, according to the decomposition products which were 

 looked upon as the most important. The discussions thus 

 called forth were very helpful in the further development of 

 the science. Everyone tried to support his own view by 

 evidence, and this could only be found in the reactions of the 

 substance. We are indebted to these discussions, therefore, 

 for a very intimate knowledge of certain classes of substances. 



The foregoing explanations will not, I hope, prove super- 

 fluous. Their purport is to render clear the importance of 

 the radical theory, the further development of which will be 

 discussed in the next lecture. 



