THE PHYSIOLOGICAL EFFECTS OF IONS 459 



effects, and that these are the effects of the hydrogen ions. 

 AH these acids have quantitatively the same physiological 

 effect when the same number of hydrogen ions are contained 

 in the unit volume of solvent. 



5. My experiments on the effects of organic acids have 

 only just been begun. Thus far I have used only four acids, 

 namely, acetic acid, lactic acid, oxalic acid, and malic acid. 

 Ten c.c. of a one-tenth normal solution of one of these acids 

 were added to 100 c.c. of a 0.7 per cent. NaCl solution. 

 The increase in weight expressed in per cent, of the original 

 weight of the muscle is given in Table IV : 



TABLE IV 

 (F=110) 



In order to decide whether we are dealing here with the 

 effects of H ions, and. in how far, we must first determine the 

 degree of dissociation of these solutions. We use for this 

 purpose Ostwald's determinations. 1 



For acetic acid, /* 100 = 15 (about), /* oo = 364 ; 

 For lactic acid, /* 100 = 38 (about), /* oo = 358 ; 

 For oxalic acid, /*200 = 338 (about), /* oo = 365 ; 

 For malic acid, /*200 = 85 (about), /* oo = 356. 



If we calculate from these figures the fraction of mole- 

 cules that are dissociated, the following values are found for 

 a for the concentrations employed: 



For acetic acid, a = - 3 Yr = 0.04 ; 

 For lactic acid, a = -$& = 0.10 ; 

 For oxalic acid, a = Iff = 0.92 ; 

 For malic acid, a -^j- = 0.23. 



i Abhandlungen der Sachsischen Gesellschaft der Wissenschaften, Vol. XV (1889). 



