350 BULLETIN OP THE UNIVERSITY OF WISCONSIN. 



case and for the particular concentration under consideration i 

 is actually equal to unity. 



It must be fully and freely admitted that the dissociation the- 

 ory has done much good in stimulating research in many lines. 

 It has been fruitful in proportion to the amount of truth con- 

 tained in it. Like other theories founded upon too narrow a 

 basis of induction, it has gradually been outgrown, — the facts 

 are too much for it. It would be difficult of course to say of any 

 theory — even of one long ago discarded — that it is entirely 

 worthless, and so the writer has no inclination to make such a 

 statement concerning the dissociation theory. And further he 

 would not be understood as having the remotest intention to be- 

 little in any way the work done by the enthusiastic adherents 

 of the theory of electrolytic dissociation, for this will no doubt 

 always form a bright page in the history of the development of 

 chemistry and of science in general. 



It is solely because of the rapid growth of the erroneous idea 

 that the deductions drawn from the indiscriminate application 

 of the simple gas equation to solutions and from the notion that 

 all well known facts harmonize with the theory of electrolytic 

 dissociation, that I have felt compelled to call attention to the 

 real status of the experimental facts underlying these deduc- 

 tions. It is hoped that this will stimulate to renewed experi- 

 mental activity, for surely our theory of solutions leaves much 

 to be desired. The analogy between gases and solutions does 

 not help us to understand even moderately concentrated solu- 

 tions ; and whenever experimental work on such solutions is 

 done, the assumption that there is chemical union between solv- 

 ent and dissolved substance calls for recognition. That there is 

 chemical union between solvent and dissolved substance, in many 

 cases at least, there can be no doubt ; and as for the osmotic pres- 

 sure, the outcome of that mutual attraction between solvent and 

 dissolved substance, its various excentricities and caprices, as ex- 

 hibited even in moderately concentrated solutions, show clearly 

 that it is closely related to, if not essentially identical with, 

 chemical affinity. Our hope in the study of solutions lies in 

 the recognition of this. The problem of solutions is pre- 



