138 THE SIGNS OF LIFE [LECT. 



current is from dilute to concentrated, i.e., with the water 

 current. 



The direction of electrical current between two unequally 

 concentrated solutions of any electrolyte depends upon the 

 relative velocities of the two ions, both of which are of course 

 travelling from concentrated to dilute solution. If the anion is 

 of higher velocity, as is the case with alkalies and most salts, the 

 current is from dilute to concentrated ; if the kation is of higher 

 velocity, as is the case with acids and some salts, the current is 

 from concentrated to dilute. (See Fig. 55.) You may be dis- 

 posed to admit provisionally, as I do, that the latter condition 

 obtains in the case of the complex organic compounds that take 

 part in the dance of life ; current of action proceeding from the 

 spot of greatest " livingness," where solution pressure is in- 

 creased --and dissociation and ionic concentration and 

 osmotic pressure. 



SOME RELATIVE IONIC VELOCITIES. 



Kation + Anion - 



NaCl Sodium 37 Chloride 63 



HC1 Hydrogen 80 Chloride 20 



NaOH Sodium 20 Hydrate 80 



CH 3 COOK Potassium 68 Acetate 32 



SOME ABSOLUTE IONIC VELOCITIES. 



(At P.D. of i volt per i cm., and Temp, of 18 C.) 



In cm. per sec. In mm. per hour. 



Hydrogen H + 0.00320 115 



Hydroxyl OH - 0.00182 65 



Sodium Na + 0.00045 Io 



Chlorine Cl - 0.00069 2 5 



Potassium K + 0.00066 24 



Acetyl CH 3 COO - 0.00036 13 



Engelmann in the course of his investigation of skin 

 currents, and Biedermann in his examination of mucous 

 currents, paid particular attention to the effects of water, and 

 of saline solutions on the normal current. Neither of these 

 authors explicitly distinguishes the physical imbibition current, 

 which must evidently have been a considerable, if not the chief 



