724 



6. ARSENICALS 



variable binding it is more likely that penetration into the cells is the major 

 factor. It has also been shown that the activity and the amount bound 

 of various arsenicals, especially those with acidic substituents, vary with 

 the pH in parallel fashion (see page 777). We must then conclude that when 

 substituent groups are placed on the phenylarsenoxide ring, the ability 



20 40 



RELATIVE MOLAR TOXICITY 



Fig. 6-6. Binding of arsenicals to erythrocytes as 



related to their toxicity. The incubation time was 



10 min. All the arsenicals are substituted phenyl- 



arsenoxides. (From Hogan and Eagle, 1944.) 



