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SCIENCE. 



[N. S. Vol. XII. No. 302. 



ists, that organic chemistry is approach- 

 ing the condition in which it will have 

 ceased to afford a profitable field for re- 

 search, and in which it must be turned 

 over for exploitation to the technologist. 

 I believe that never in its history has there 

 been a time when more directions for truly 

 original work were visible than to-day, and 

 if I have urged the claims of inorganic 

 chemistry to greater recognition, I do not 

 believe that this should be accomplished 

 by abandoning the investigation of carbon 

 compounds, but rather by increasing the 

 number of workers. To those trained in 

 the older organic chemistry of twenty years 

 ago, but who have not followed its recent 

 development, it may indeed seem that 

 formula worship is still supreme, and that 

 further evolution, in a theoretical sense, 

 has been arrested. It cannot be imagined, 

 however, in these times of progress, when 

 even analytical chemistry is beginning to 

 lose its purely empirical nature, and to as- 

 sume a scientific aspect, that the organic 

 chemist will be content with indefinitely 

 developing the ideas inhei'ited from the 

 past, without originating, or at least assim- 

 ilating essentially new conceptions. Two 

 courses are open to him if he would remain 

 a scientist : the one, to admit that carbon 

 chemistry has reached its limit of develop- 

 ment, and to abandon it for other more 

 profitable fields ; the other, to seek new di- 

 rections of work in this field, to devise new 

 methods, suggest new hypotheses and apply 

 principles originating in other provinces of 

 science. My present object is to point out 

 some of the newer lines of work which ap- 

 pear to me to be particularly important, 

 some of which are already well known, 

 while the significance of others, while doubt- 

 less apparent to some, does not yet seem to 

 be generally recognized or insisted on. 



Every chemical student is more or less 

 familiar with the remarkable theoretical 

 growth of carbon chemistry between 1830 



and 1860, leading up to the valence hypoth- 

 esis and the hypothesis of the linkage of the 

 atoms, and culminating in the fully de- 

 veloped structui-al formula, representing 

 schematically the relation of the atoms in 

 organic molecules. This was followed by 

 a period almost devoid of theoretical de- 

 velopments, but characterized by intense 

 activity in devising synthetical methods and 

 applying them to building up new or already 

 known compounds, or in systematically de- 

 composing complex bodies, with the sole 

 object of establishing their structural for- 

 mulas. The beautiful researches based on 

 the benzene ring theory of Kekule, the syn- 

 thesis of alizarine by Graebe and Lieber- 

 mann, and of indigo by Baeyer, brilliantly 

 conceived and executed as they were, threw 

 not a single further ray of light on the 

 deeper problems of chemistry, and were of 

 much less theoretical significance than the 

 discovery, in 1830, of the transformation of 

 ammonium cj'anate into urea. The deter- 

 mination of the structural formula became 

 the final end of nearly all organic chemical 

 research, in so far as this was prompted by 

 scientific leather than practical motives. 



The structural formula once developed, 

 the compound possessed little further inter- 

 est, except in so far as its transformations 

 could lead to the setting up of similar for- 

 mulas for other bodies. When I was a stu- 

 dent of organic chemistry, in the eighties, 

 formula worship was rampant. Neither in 

 America nor in Germany was I led to be- 

 lieve that organic chemistry could have 

 any other aim and end than making new 

 compounds and studying their constitution. 

 A new compound ! How the soul of the 

 young investigator thrilled with joy when 

 his substance showed a new percentage of 

 carbon and hydrogen, a new melting or 

 boiling point ; this was something no god 

 nor mortal had yet beheld. The constitu- 

 tional formula was then deduced, if possi- 

 ble; if impossible, then at least one which it 



