266 C.-E. A. WiNSLOW AND E. E. LOCHRIDGE 



— phenol, thymol, and resorcinol — was affected only to a barely 

 appreciable degree. The action when it occurs is explained by the 

 power of suspended particles to remove dissolved substances by a 

 process of adsorption, and the possibility suggests itself that the 

 removal of ions by large organic molecules in true or colloidal 

 solutions may be of an analogous character. Whatever the cause, 

 this phenomenon must prove of far-reaching importance in bacteri- 

 ology. Such facts as the observed multiplication of bacteria, when 

 water samples are stored in glass bottles, may be the result of a 

 removal of inhibiting substances by the adsorptive action of glass 

 surfaces. 



A considerable body of evidence in the field of anim.al physiology 

 bears out these conclusions obtained from the study of bacteria and 

 other plants. A fairly full summary of this literature may be found 

 in the reviews of Cohen (1903) and Hamburger (1904). The work 

 of Kahlenberg (1898) and other observers, who have shown that the 

 taste of dilute solutions is in many cases due to the specific properties 

 of the dissociated ions, is of interest. Studies which have been 

 frequently cited were made by Loeb (1897 and 1898), and recently 

 reprinted (Loeb, 1905), on the influence of free ions upon frog's 

 muscle. The gastrocnemius muscle absorbs water and increases its 

 weight in the presence of slight traces of acids or alkalis, and Loeb con- 

 cluded that for the inorganic acids and bases this increase in weight 

 is solely a function of the number of hydrogen and hydroxyl ions in 

 the unit of volume. This sweeping conclusion is hardly borne out 

 by his experiments. With the organic acids there was no relation 

 whatever. Trichloracetic acid, almost entirely dissociated, and 

 lactic acid, with only 11 per cent dissociation, gave practically the 

 same results. With a series of 11 different organic acids of every 

 degree of dissociation, the individual variation in weight-increase, 

 with 0.009 normal solutions, ranged only between 3.9 per cent and 

 7.2 per cent. 



A very significant line of physiological investigation concerns the 

 binding of free ions by organic molecules of large size. In one of 

 the most recent communications on this subject, Stiles and Beers 

 (1905) have shown that the effect of calcium chloride, barium potas- 

 sium chloride, and sodium nitrite upon plain, cardiac, and striped 



