ELECTROLYTES IN LIVING MATTER 95 



and 1900; namely, that the normal qualities, especially the normal 

 irritability, of animal tissues depend upon the presence in these tissues 

 of Na-, K-, Ca-, and Mg-ions in the right proportion ; that these ions are 

 at least partly in combination with colloids (proteids or higher fatty 

 acids or possibly carbohydrates), and that any sudden change in the 

 relative proportions of these ion lipoids or ion proteids or ion carbo- 

 hydrates alters the properties of the tissues and gives rise to an activity 

 or an inhibition of the activity, according to the sense in which the change 

 takes place. Finally, I believe that the natural rhythmical processes 

 such as heartbeat, respiration, etc., are due to a substitution of certain 

 metal ions for others, these substitutions being caused by the enzymatic 

 processes going on continually, and by which, among others, metal ions 

 are freed from certain combinations, and rendered available for others, 

 as seems to be the case in the action of rennet in the coagulation of 

 milk. We certainly understand by this hypothesis why the combina- 

 tion of the Na-, K-, Ca-, and possibly Mg-salts is so important for life 

 phenomena, especially those of animals. 



3. THE REACTION OF LIVING * MATTER AND THE ROLE OF BICAR- 

 BONATES FOR THE PRESERVATION OF LlFE 



Not only the life of the aquatic animals but the life of every cell is 

 passed in a solution of electrolytes. It had generally been assumed 

 that the liquids in the animal tissues, as well as the sea water, had an 

 alkaline reaction, while the liquids of the tissues of plants had an acid 

 reaction. This assumption was founded upon the titration method. 

 Physical chemistry altered the conception of alkalinity, and measured 

 it by the concentration of the free hydroxyl-ions. Hober* was the first 

 to make use of the methods required to determine the concentration 

 of the hydroxyl-ions in the blood, and found with the aid of gas batteries 

 that the blood was slightly alkaline. His method was defective in a 

 detail, and later Friedenthal,f Franckel,J Farkas, and Hober himself 

 showed that the concentration of the hydroxyl-ions in the blood is not 

 higher than in distilled water. Cottrell and I found the same for sea 

 water. Friedenthal showed also that the liquids of the tissues of ani- 

 mals and plants are practically neutral. We therefore may draw the 

 conclusion that life phenomena occur in a neutral liquid. The forma- 

 tion of CO 2 is one of the most general processes in living tissues. Be- 

 sides, other acids (e.g. lactic acid in the muscle) are formed in metabo- 



* Hober, Pftitger's Archiv, Vol. 8l, p. 535, 1900. 



f Friedenthal, Zeitsch. fur allgemeine Physiologie, Vol. I, p. 56, 1902. 



j Franckel, Pftiiger's Archiv, Vol. 96, p. 601, 1903. 



Loeb, Pfluger's Archiv, Vol. 99, p. 637, 1903 ; and Vol. 101, p. 340, 1904. 



