294 THE REVIVAL OF INORGANIC CHEMISTRY. 



and nitrogen. This was the first of a series of innumerable syntheses 

 which have fully disposed of the idea that any fundamental distinction 

 exists between inorganic and organic compounds. Although we have 

 not yet made albumin in the laboratory, we all expect that if will be 

 done, and nearly every chemist now believes that even the properties 

 of living protoplasm are due, not to any peculiar vital force inherent 

 in the protoplasm itself, but to the special properties ot the carbon, 

 hydrogen, oxygen, nitrogen, phosphorus, and other elements of which 

 it is composed. My subject does not permit me to consider in detail 

 how the idea of organic chemistry, as the chemistry of compound radi- 

 cals, was evolved; how the radical theory was replaced by the concep- 

 tion of the molecule as a unit; how, in 1853, the theory of valency 

 began to develop, and how this, with the type theory, the theory of the 

 linkage of atoms, and the constant tetravalency of carbon, led, in the 

 early sixties, to our present conceptions of the structure of organic 

 molecules. With the advent of the fully developed structural formula, 

 the brilliant progress of organic chemistry toward fuller theoretical 

 development came to an end with remarkable suddenness. Kekule's 

 ingenious and fruitful theory of the benzene ring, suggested in 1865, 

 was an application to a particular class of compounds of principles 

 already established, but involved no fundamentally new conceptions. 

 Organic chemistry entered upon what has aptly been termed a period 

 of "formula worship." The establishment of the constitutional formula 

 became the highest aim of the devotees of this cult, against which but 

 few chemists, for example Kolbe and Mendelejeff, have had the courage 

 to protest. In pursuing this aim the organic chemists have unques- 

 tionably accumulated an enormous mass of valuable information and 

 detail; have discovered new methods of synthesis, new laws of more or 

 less special application, and new compounds of practical value; but, 

 with all their labors, the ordinary structural formula of to-day means 

 no more than it did in 1865. In stereo-chemistry, however, the devel- 

 opment of the structural formula in space of three dimensions, organic 

 chemistry has shown real progress, especially since 1887, when LeBel 

 and van't Hoff's theory of the asymmetric carbon atom, which was pro- 

 posed in 1874, but which slumbered almost forgotten, was revived by 

 Wislicenus. At present the most important developments of struc- 

 tural chemistry, both organic and inorganic, unquestionably have the 

 question of space relation as their basis. 



The development of inorganic chemistry presents some marked dis- 

 tinctions from that of organic chemistry. Up to the year 1820 nearly 

 all the important discoveries and generalizations came from the inor- 

 ganic side. Richter's discovery of the law of equivalents ; the researches 

 of Scheele, Cavendish, Priestley; the development of the theory of 

 oxidation by Lavoisier; the atomic hypothesis of Dal ton and his laws 

 of constant and multiple proportions, and the placing of them on a 

 firm foundation by the remarkable labors of Berzelius ; Gay Lussac's 



