April 28, 1899.] 



SCIENCE. 



605 



regarded as ternary or quaternary. Later 

 he extended the dualistic conception to 

 these also, adopting the idea of Lavoisier 

 that they are binary compounds of oxygen 

 with compound radicals, composed of car- 

 bon, hj'drogen and sometimes nitrogen, a 

 view which he developed further and never 

 wholly abandoned. In 1817 we find Leo- 

 pold Gmelin maintaining that organic com- 

 pounds are the products of a vital force and 

 cannot be produced artificially. This view 

 was entertained hy Berzelius even as late as 

 1827 or later. Berzelius attributed the 

 formation of organic compounds, with their 

 relatively weak positive and negative 

 characters, to peculiar electrical conditions 

 existing in the organism. We cannot re- 

 produce these conditions in the laboratory, 

 and, therefore, cannot produce organic com- 

 pounds artificially. Those transformations 

 which we are able to eifect are always from 

 the more complex to the simpler. We can 

 isolate the intermediate stages in the break- 

 ing-down of organic matter into carbon 

 dioxide, water and ammonia, that is, we 

 can follow the change of matter from the 

 organic to the inorganic, step by step, but 

 we cannot reverse the process and build up, 

 nor can we hope to do so in the future. This 

 opinion of Berzelius marks the widest gulf 

 between organic and inorganic chemistry, 

 a gulf too wide for human power to bridge. 

 How dangerous it is to set limits to the 

 power of science ! But one year later, in 

 1828, Wohler announced his discovery that 

 urea, a body of animal origin, could be pro- 

 duced from ammonium cyanate, a sub- 

 stance, which, in its turn, can be built up 

 from its constituent elements, carbon, 

 hydrogen, oxygen and nitrogen. This was 

 the first of a series of innumerable synthe- 

 ses which have fully disposed of the idea that 

 any fundamental distinction exists between 

 inorganic and organic compounds. Al- 

 though we have not yet made albumin in the 

 laboratory, we all expect that it 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 of 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 radicals, was evolved; how the 

 radical theory was replaced by the concep- 

 tion of the molecule as a unit ; how, in 

 1853, the theory of va,lency 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 develop- 

 ment came to an end with remarkable sud- 

 denness. 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 en- 

 tered upon what has aptly been termed a 

 period of ' formula worship.' The establish- 

 ment 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 dis- 

 covered new methods of synthesis, new 

 laws of more or less special application and 

 new compoundsof 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 development of the structural formula 

 in space of three dimensions, organic chem- 



