zi6 THE POPULAR SCIENCE MONTHLY, 



to the valuable substances included in the materia medica, he would 

 stop when he had established the fact that this substance just born 

 has such and such medicinal properties. He might discover a few sub- 

 stances in this way, but, unless work of another kind were going on 

 simultaneously, which would furnish him with new methods, with new 

 guiding principles, the possibilities of new discoveries would soon be 

 exhausted. It is absolutely necessary, then, that purely scientific and 

 abstruse problems should engage the attention of chemists, if the sci- 

 ence is to grow ; and it is further necessary that the science should 

 grow, in order that new methods for the discovery of new substances 

 may be introduced. It is the chemist proper who furnishes the 'new 

 method ; it may be that the chemist proper also discovers the valuable 

 remedy, though one who simply applies the truths of chemistry may 

 make the discovery. 



As a matter of fact, it can be shown that it is to the purely scien- 

 tific chemist, working with the main object of building up the science, 

 that we owe the discovery of most valuable remedies, at least of those 

 which are strictly speaking chemical compounds. I select for this pur- 

 pose two substances which have but comparatively recently found their 

 places in the materia medica viz., chloral and salicylic acid. How 

 and by whom were these substances discovered and introduced into 

 medicine ? 



Nearly fifty years ago the great master Liebig undertook the study 

 of the decomposition which alcohol undergoes when treated with chlo- 

 rine. Other observers had noticed the fact that alcohol is decomposed 

 by chlorine and that an oily product is formed, but the nature and com- 

 position of this product were unknown. Liebig undertook then simply 

 to study this decomposition for the sake of throwing light upon the 

 general subject, the action of chlorine upon alcohols. His investiga- 

 tions soon led him to the discovery of a new substance which pos- 

 sessed peculiar chemical properties, distinguishing it from all other 

 compounds then known. This was chloral the name being derived 

 from the first syllable of chlorine and the first syllable of alcohol. Of 

 the action of this substance upon the system, Liebig did not dream ; but 

 the study of its properties which he made at that time furnished the 

 material that enabled Liebreich, forty years later, to dream in a very 

 rational manner concerning its action upon the system. Liebreich's 

 discovery of the value of chloral could not have been made by one 

 unversed in chemistry. His experiments were undertaken in the true 

 scientific spirit, and were suggested by a purely chemical method of 

 consideration. 



Among other facts concerning chloral which had been established 

 by Liebig was this that in the presence of alkalies it breaks up into 

 formic acid and the substance which we now know by the name chlo- 

 roform. Chloroform was thus discovered by Liebig at the same time 

 with chloral, but the action of the former upon the system was as little 



