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SCIENCE 



[N. S. Vol. XXX. No. 775 



leagues seize eagerly upon our organic sol- 

 vents for use in their inaccurate methods 

 for the determination of molecular weights, 

 and upon our organic indicators to aid 

 them in poor analyses. They clamor for, 

 and would die without, our medicines, such 

 as whiskey {imitation or any kind), atro- 

 pine, quinine and ether, our cane sugar 

 and glucose and our artificial breakfast 

 foods; and their dainty daughters could 

 not so entrancingly lure sweethearts with- 

 out our beautiful dyes in their silks and 

 cheeks, our delightful synthetic violet per- 

 fume in their handkerchiefs and our arti- 

 ficial pineapple, strawberry and vanilla in 

 their dangerous embryonic pastries and 

 ices. This same compound-making, this 

 so-called old style organic chemistry, with 

 its reactions and methods, is not only of 

 the very greatest importance to science and 

 economy, but is becoming more so every 

 day. 



But we have another side to organic 

 chemistry, which appeals to the physical 

 and inorganic chemists, and so much so, 

 indeed, that they try to appropriate it in 

 their text-books as part of their own do- 

 main: namely, the quantitative study of 

 organic reactions. In pointing out the 

 problems that busy our organic chemists, 

 perhaps I can not do better than to bring 

 to your attention some of the researches 

 that have been, or are being, completed and 

 still other problems whose solution is of the 

 greatest importance to the chemical world. 



The question of fundamental importance 

 in any reaction, and the one that must be 

 answered first, is: What are the constitu- 

 ents that are really uniting or reacting to 

 give the end products? When this is 

 known we must then determine quantita- 

 tively the natural constants which govern 

 the concentrations of the reacting constitu- 

 ents at any time and their velocity of 

 transformation and final equilibrhim. 



These constants are just as characteristic 

 as are the melting points and molecular 

 weights for each set of substances under 

 definite conditions, that is, in defimite con- 

 centrations, in definite solvents, at definite 

 temperatures and exposed to definite wave- 

 lengths of light of given intensity, etc. 



The question as to what are the really 

 active constituents of a given reacting mix- 

 ture, whether it be one of organic or inor- 

 ganic substances, is not always easily an- 

 swered. Do the molecules which we put 

 together unite or do their simple or com- 

 plex ions enter into combination? Some 

 of our prominent physical chemists tell us 

 "that most chemical reactions, if not all, 

 are reactions between ions; molecules, as 

 such, do not enter into the reaction at all. ' ' 

 On the other hand, other prominent phys- 

 ical chemists go perhaps too far in the 

 other direction: they elect their colleagues 

 with brotherly love to life membership and 

 exalted rank in their own Ananias Club 

 and declare that "whoever claims that the 

 instantaneous chemical changes in aqueous, 

 or other, conducting solutions take place 

 because of the fact that these solutions are 

 electrolytes (or in current phraseology, be- 

 cause they contain ions), must assume the 

 burden of proving his proposition," a 

 statement to which we must all agree. 

 Both of these factions of physical chemists, 

 I believe, fail to weigh judicially all of the 

 experimental evidence at hand. The cham- 

 pions of the union of ions as the cause of 

 chemical reactions argued from such facts 

 as the failure of dry hydrochloric acid and 

 dry ammonia to form ammonium chloride. 

 We can challenge them to prove beyond 

 question (1) that the molecules do not react 

 in the presence of moisture, (2) that the 

 gases were perfectly dry, (3) that the gases 

 did not actually slowly unite. They could 

 answer that no apparent union took place 

 in a great length of time: but we could 



