268 Wisconsin Academy of Sciences , Arts and Letters. 
when the proper septum is chosen. Whether substances can 
be separated by dialysis or not does not depend at all upon 
their crystalline or non-crystalline nature as is so commonly sup¬ 
posedl, but upon their affinity for the septum employed. After 
what has been said above, it is evident that stirring the liquids 
hastens dialysis. 1 
Several experiments in addition to those here described have 
been performed, but as I hope to continue the experimental 
work on dialysis their presentation will be reserved for a later 
communication. 
GENERAL REMARKS. 
The conclusion reached above that the process of osmosis de¬ 
pends upon selective solubility (in other words, upon the af¬ 
finities involved) is in agreement with what Overton 2 * * * * has found- 
in his physiological studies. The importance of the recognition, 
of the true nature of osmotic processes for progress in physi¬ 
ology can hardly be overestimated. 
From the time of Dutrochet all investigators who worked on 
osmosis experimentally with different membranes and various 
liquids have been impressed with the important role of the na¬ 
ture of the membrane in determining whether osmosis would 
occur at all or not, and if so, in what direction. The follow¬ 
ing quotation taken from the article of LTTermite, cited above, 
shows how clearly he had grasped the situation. ‘‘Je pense 
avoir demontre par la discussion des experiences de mes de¬ 
van ciers et des miennes, que Fendosmose n’est point le resultat 
d’une force particuliere, mais de Faffmite elle-meme en etendant 
1'acceptation de ce mot a 1 ’attraction capillaire qui en est le 
premier degre ’ ’. I should also like to quote the opinion of 
Raoult, which he voiced in a letter written January 7, 1897,. 
to Prof. W. D. Bancroft, and which, through the latter 7 s kind- 
i Since the above was written it came to my notice that in 1848 
Jolly, (Lieb Ann. 68, 6) refers to a case where he shook the dialyzer 
to hasten the process. 
2Vierteljahrsschr. d. naturforsch. Ges. in Zurich, 44, 88 (1899). See 
also the discussion in chap. 5 of Hober’s Physik. Chem. d. Zelle u. 
Gewebe, Leipsig, (1902). Compare also Livingston, The Role of Dif¬ 
fusion and Osmotic Pressure in Plants, Chicago (1903). 
