DEPARTMENT OF MARINE BIOLOGY. 



205 



It will be noted that the living cell offers considerable resistance to the 

 entrance of both of these acids as compared with the dead cell. A large series 

 of other acids were also studied and the relative time for penetration from 



Table 1. 



n/100 and n/200 concentration was determined. In table 2 the series of acids 

 so obtained is compared with their various physical properties, degree of 

 dissociation, effect of lowering the surface tension of water, diffusion constants, 

 and lipoid solubility. In this way an idea may be gained of the property on 

 which rapid penetration of an acid depends. The toxicity of the acids for the 



^Concentration which just kills in 20 hours. 



^Insol. in xylol from n/100 cone, in water but slightly soluble from n/10 cone 

 from n/10 cone in water. From unpublished experiments. 



Remaining acids insoluble 



