n8 PHYSICAL CHEMISTRY 



a membrane of larger surface and less thickness was made. On 

 connecting one calomel electrode with the dilute solution and 

 the other through the glass tube with the concentrated solution, 

 an emf of 25 mv was measured with the potentiometer, the 

 dilute side being positive. 



The other type of membrane is an organic base, which, accord- 

 ing to Beutner, combines with the anion of the electrolyte to 

 form a salt soluble in the membrane. His experiment was re- 

 peated with o-toluidin, in the same manner as with salicylic 

 aldehyde, and obtained 27 mv with the Dolezalek electrometer. 

 In order to use the potentiometer, chloroform was added to the 

 toluidin to make it heavier, and 80 mv obtained, the dilute side 

 being negative. 



In order to obtain larger membranes, parchment paper tubes 

 were soaked in salicylic aldehyde, toluidin or anilin. In each 

 case the emf was what would be expected with parchment paper 

 alone, but was maintained for a longer time. For this reason 

 it seems possible that the organic liquid was effective in retard- 

 ing the wetting of the paper with consequent enlargement of its 

 pores. If this is true it shows a method of finding the initial 

 emf with parchment paper. Although with toluidin alone the 

 dilute side is negative, when it is applied to parchment paper 

 the dilute side is positive. The emf with n/100 and n/1000 KG 

 was 59 mv, and substituting toluidin, was 52 mv. 



According to Loeb and Beutner (1913) a solution of lecithin 

 in m-cresol acts in the same way as salicyl aldehyde when used 

 as a membrane in a concentration cell. But since higher fatty 

 acids could be substituted for lecithin, it seems probable that 

 fatty, or glycerophosphoric acid, formed by the decomposition 

 of lecithin was the active agent. 



Bioelectric Phenomena 



The electromotive forces produced by living matter have al- 

 ways been a subject of interest, if not amazement. The shock 

 of some electric fish is several hundred volts, and may be felt 

 while the fish is entirely submerged in sea water. On the other 

 hand, the ordinary electric potential differences observed in living 

 matter never reach 0.1 volt. The secret of the electric organ 

 lies in the connection of the elements in series. Brunings ob- 



