IQOS] 



POND— SOLUTION TENSION AND TOXICITY 



248 



silver on the equimolecular basis. The same relative toxicity is 

 maintained here as in those tables, although greater concentration of 

 both salts is required for total inhibition. 



Here the two salts are practically equitoxic, so that in some cases, 

 with increasing concentration of the enzyme, salts, which arc equitoxic 

 become unequal in toxicity, while others that are not equitoxic under 

 certain conditions become so under other conditions. Perhaps the 

 only conclusion that can be safely drawn from this group of tests is that 

 the concentration of the enzyme influences relative toxicity, and that 

 a relation which holds for one concentration of the enzyme may not 

 hold for another four or five times greater. 



RELATIVE TOXICITY OF EQUICATIONIC SOLUTIONS 



By calculation" it may be determined that copi)er and lead of 

 m/2048 concentration are cquicationic, and by examination of my 

 results it is seen that those solutions are about equitoxic. On the 

 other hand, w/1971 of barium is cquicationic with copper m/2048, 



TABLE XX: Ethyl butyrate 

 Barium, lead, copper, and potassium in contemporaneous lest 



BARIUM 



Enzyme 0125 per cent. Incubation 4 hours at 35° C. 



" All of the cquicationic calculations were made for me by Dr. Wm. N. Berg 

 of the Laboratory of Biological Chemistry of Columbia University. 



