XXX 



were a generic difference between organic and inorganic substances, no 

 chemical difference could be assumed. He was convinced that there 

 could be only one chemistry, and took upon himself the task of effecting 

 a scientific connexion between the two branches. His investigation of 

 fulminic acid had already carried him in this direction. He and Gray- 

 Lussac had found it to be a compound of carbon, nitrogen, and oxygen, 

 and he then discovered the corresponding compound of cyanogen with 

 sulphur, and investigated melam and its other products of decomposi- 

 tion. 



After Graham had established the tribasic character of the common 

 phosphates, Liebig showed that some organic salts had a similar consti- 

 tution. But peculiar difficulty was presented by the constitution of 

 certain neutral organic substances, such as alcohol, ether, essential oils, 

 &c. Liebig endeavoured to get a key to their constitution by investi- 

 gating the action of simple materials upon them, such as chlorine and 

 bromine, &c, and often led his students into this line of work. 



In this way a great number of the most remarkable substances were 

 discovered, some of which in future years were of practical use, though 

 the object of the investigator was purely scientific. Thus Liebig dis- 

 covered chloral long before Liebreich discovered its medicinal qualities. 



These labours of Liebig appeared at first to the masses as a useless 

 toying with chemistry, and were often laughed at. To this the very 

 unusual names selected may possibly have contributed : as an instance 

 we may mention the following : — "When he found out the composition 

 of a to him most important compound, which he looked upon as alcohol 

 which had parted with some of its hydrogen, he named, the new sub- 

 stance Aldehyde, an abbreviation of alcohol dehydrogenisatus. This 

 strangely sounding word excited the astonishment or even the derision 

 of those who had been accustomed to hear new mineral substances 

 named either after the places where they had been discovered or after 

 their inventors, or after distinguished or influential persons, or to hear 

 people speak of Scheele's and Schweinfurt green or Berlin blue. 



For Liebig the chief difference between organic and inorganic sub- 

 stances was that the former contain compound radicals, whereas the 

 latter are similarly built up of elements. A joint research of Liebig and 

 Wohler on the subject of compound radicals was fruitful of important 

 results. They examined oil of bitter almonds and benzoic acid, and 

 discovered the radical benzoyl, a group of three elements, which was 

 capable of combining like an element with chlorine, hydrogen, &c. 



Berzelius was greatly interested in this discovery, and declared that it 

 was the dawn of a new day in Vegetable Chemistry. He went so 

 far as to say that he would like to see the first radical discovered, 

 which consisted of more than two simple substances, named Proin or 

 Orthrin. 



No man is infallible ; and Liebig, of course, made occasional mistakes. 



