i 9 2 BIO-CHEMICAL JOURNAL 



gelatine of the above experiment, as regards its conductivity, when 

 re-dissolved to original volume, with the conductivity of the gelatin 

 solution at 10 and at 53. The ash from 100 c.c. of the gelatin 

 solution weighed 0*0262 gram, it was re-dissolved in 96*6 c.c. of 

 distilled water (to allow for the volume of the gelatin), the whole of 

 it not going into solution. Now the conductivity of the gelatin 

 solution was found at 6*2 C. to be 141 gemmhos, that of the re- 

 dissolved ash was 270 gemmhos. It is obvious that this is more than 

 sufficient to account for the additional electrolytes split off on heating. 

 It also confirms the view already expressed that inorganic electrolytes 

 are held in some kind of combination by gelatin. Since they are also 

 separated to a certain degree by warming, the combination in question 

 is in all probability of the nature of adsorption. 



The various substances which increase the velocity of adsorption 

 also affect the final equilibrium position but in the opposite direction 

 to that in which it is affected by heat. The action of neutral salts is 

 the most interesting and of the greatest practical and theoretical 

 importance. Sodium chloride has a very striking effect, even in very 

 low concentration, as the following experiment shows : 



Solution of congo-red 0*004 P cr cent, containing various 

 percentages of sodium chloride. After a circle of paper had lain in 

 each for 2 hours the following colorimeter readings were obtained : 



Percentage of Percentage of dye Percentage of Percentage of dye 



NaCl left in solution NaCl left in solution 



O 85 O'02 33 



0-0005 77 o-i 25 



o-ooi 71 0-2 1 6 



0-005 50 



The effect of sodium chloride, then, appears to be proportional 

 to its concentration but not in direct linear proportion. The fact that 

 in so weak a concentration as 0-0005 per cent, an obvious effect is 

 produced indicates that the action of inorganic electrolytes is rather to 

 be brought into relation with the well-known effect of these bodies on 



D 



typical colloids, rather than with the precipitating action of alcohol, 

 which requires a much higher relative concentration in order to 

 produce a comparable effect. In investigating this action of electrolytes 



