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THE POPULAR SCIENCE MONTHLY.— SUPPLEMENT. 



Great as were his services in every depart- 

 ment of chemistry, it is organic chemistry that is 

 the most indebted to him — indeed, he is often 

 called the father of it. If the foundations had 

 been to some extent laid before, it cannot be dis- 

 puted that Liebig did more than any other chem- 

 ist toward building up the structure. 



Animal or vegetable substances, or organic 

 matter, had often been the subjects of chemical 

 researches when Liebig entered the arena of sci- 

 ence, and it is known that all of them, unlimited 

 as is their number, contain carbon, hydrogen, 

 nitrogen, and oxygen, in certain proportions ; 

 but, as their origin in plants and animals was 

 supposed to depend on other than chemical 

 forces, their chemical relations to each other, 

 and to inorganic mineral matter, were supposed 

 to be different also. The vital forces under the 

 influence of which all these organic matters origi- 

 nated were held to impress on them a peculiar 

 and mysterious stamp. 



The conviction arose very early in Liebig's 

 mind — it may almost be said to have been born 

 with him — that, even if there were any generic 

 difference between organic and inorganic matter, 

 so far as the vital forces were subject to chemical 

 laws, no chemical difference existed. He was 

 convinced that there could be but one chemistry, 

 and considered it to be his mission to bring or- 

 ganic and inorganic chemistry into scientific har- 

 mony. His experiments on fulminating oxide, 

 which he and Gay-Lussac recognized as a com- 

 bination of cyanogen and oxygen, led him to this 

 path ; he then discovered the corresponding sul- 

 phuric combination of the compound radical cy- 

 anogen to be sulphur cyanide, and traced the 

 products of decomposition in melon, cyanic oxide, 

 melam, and other bodies. 



Graham had shown that among the mineral 

 acids there are some bases — phosphoric acid, for 

 instance — which are saturated by one, two, or 

 three equivalent bases ; Liebig proved that it was 

 the same with the organic acids having several 

 bases. 



The nature of certain neutral organic matters 

 — alcohol, ether, and many of the volatile oils, 

 generally regarded as being of an almost mysteri- 

 ous character — was the most obscure, and dif- 

 fered most essentially from the mineral substances. 

 Liebig sought to throw light on their nature and 

 composition, particularly by trying the effect of 

 simple organic matters on them, such as bromine 

 and chlorine, and he frequently directed the at- 

 tention of his pupils to it. In this way a number 

 of remarkable substances were discovered, which 



were afterward turned to all sorts of practical 

 uses, although they had been discovered with no 

 other idea than their scientific value. Thus chlo- 

 ral was discovered by Liebig several decades be- 

 fore Liebreich found out the narcotic properties 

 for which it is now manufactured wholesale. The 

 names given to these products by Liebig showed 

 the exclusively scientific aims he had in view. 

 Thus, by the word chloral he meant to indicate 

 that it was produced by the action of chlorine 

 gas on alcohol. He wished not only to think in 

 chemical formulas, but, when possible, to express 

 himself in them also. 



These researches appeared at first to the mul- 

 titude like useless chemical child's play, and to 

 this his unusual nomenclature may have con- 

 tributed. When, for instance, he had succeeded 

 in producing what he considered a very impor- 

 tant preparation, alcohol detached from hydrogen, 

 he called it aldehyde, an abbreviation of alcohol 

 dehydrogenisatus. This queer -sounding name 

 called forth horror and ridicule among those who 

 were accustomed to hear newly-discovered min- 

 erals called after the places where they were dis- 

 covered, the discoverers, or some celebrated per- 

 sonage, as Scheele's or Schweinfurt green, or 

 Prussian blue. Had he called aldehyde Parisin, 

 Gay-Lussacin, Giessenin, or' Berzeliusin, nobody 

 would have been scandalized. 



For Liebig, the only distinction between inor- 

 ganic and organic chemistry was that the former 

 was concerned with simple radicals, the latter 

 with compound. An investigation in this direc- 

 tion, which he conducted with his friend W Shier, 

 led the way for others. Wohler had been a pupil 

 of Gay-Lussac and Berzelius, and in these general 

 scientific questions he was on an equality with 

 Liebig. Liebig was doubly fortunate in having 

 had a teacher like Gay-Lussac in his youth, and 

 a friend like Wohler for the whole of his life. 

 They made experiments together on oil of bitter- 

 almonds and benzoic acid, and discovered the first 

 radical consisting of three elements, the basis of 

 a series of combinations to which they gave the 

 name of benzoyl (basis of the benzoic series). 

 It was demonstrated that a certain group of atoms 

 of carbon, hydrogen, and oxygen (14 C + 5 H + 

 2 0) contains benzoyl in a long series of combi- 

 nations. Benzoic acid was benzoyloxide ; oil of 

 bitter-almonds, hydrobenzoic acid ; further, ben- 

 zoyl chloride, benzoyl bromide, benzoyl iodide, 

 benzoyl cyanide, benzoyl sulphide, etc., were ex- 

 hibited, in which the simple radical benzoyl was 

 found as unchanged as arsenic, or any other sim- 

 ple element in arsenic oxide, arsenic hydride, 



