PROCEEDINGS OF SECTION D. 491 



Subsequent investigations by Maillard (7) on the toxicity of solutions 

 of copper sulphate to which sulphates of the alkalies has been added ; by 

 Eckardt (8), on the relation of the velocity of diffusion to toxicity ; by 

 Schuerlen and Spiro (9), Spiro and Bruns (10), Roemer (U), and Bial 

 (12), on the action of antiseptics; by Hober and Kiesow (13), Kastle 

 (14), and Kahlenberg (15), on the taste of dissolved electrolytes ; and by 

 Loeb (16), on the absorption of water by muscles, placed the importance 

 of electrolytic dissociation in life phenomena among the established facts 

 of biological science. 



This role of electrolytic dissociation in life phenomena suggested 

 that the action of electrolytes upon living tissues was to be attributed to 

 their ions. The fact, however, that in the case of non-electrolytes, and, 

 probably, also in the case of some electrolytes (17), the undissociated 

 molecules of dissolved substances may unquestionably affect living tissues, 

 suggested a chemical rather than a physical explanation; and in 1899 

 Loeb (18) suggested that the ions of an electrolyte diffusing into a living 

 tissue combined with, or altered chemically, some constituent of the tissue. 

 He based his arguments in the first place upon the different properties 

 exhibited by a tissue when placed in solutions of different electrolytes. 

 This dependency of the properties of an organism or of a ti>sue upon the 

 nature of the ions diffusing into it is very well illustrated by the absorp- 

 tion of water by muscles in different solutions which, as Loeb showed 

 (16), presents marked analogies to the absorption of water by the different 

 soaps of the alkalies and alkaline earths. Further illustrations were, at 

 the time, afforded by the experiments of Biedermann (19), Ringer (20), 

 Howell and Cooke (21), Locke (22), and Loeb (23), on the influence of 

 electrolytes upon the nature and duration of the contractions of contrac- 

 tile tissues placed in solutions of various electrolytes. More recently, 

 however, the manifold instances of control by chemical agencies of life 

 phenomena, such as muscular irritability (23a), parthenogenesis (24), 

 regeneration (24a), hybridisation (25). maturation (26), heliotropism (27), 

 galvanotropism (27a), etc.. have multiplied enormously our examples of 

 the dependency of the properties of a tissue upon the nature of the sub- 

 stance diffusing into it. This change of properties in different solutions 

 is precisely what we should expect were different chemical compounds 

 formed in the tissues when placed in the various solutions. In the second 

 place, Loeb based his argument for the existence of definite compounds 

 between some constituent of a tissue and the ions of an electrolyte 

 diffusing into it upon the definite reactions called forth from a tissue by 

 definite ions, examples of which are afforded by the unique position of 

 the salts of the heavy metals in regard to toxicity, and the almost equally 

 unique position of the salts of the alkaline earths in regard to proto- 

 plasmic irritability and secretion (28). In a subsequent paper, in 

 February, 1900 (29), Loeb reiterated his conclusion that the ions of an 

 electrolyte on entering a tissue combined with some constituent of the 

 tissue, presumably proteid, and he conferred upon these compounds the 

 name " ion-proteids." Independently, and almost simultaneously, Paull 

 (30) arrived at identical conclusions, and also gave the name " ion-pro- 

 teids" to the compounds formed; while T. W. Richards (31). also in 

 February, 1900, pointed out that some of the phenomena of taste could 

 best be accounted for by supposing that the ions of the electrolytes 

 entered into combination with some constituent of the tissues affected. 



