i9o8] 



POND— SOLUTION TENSION AND TOXICITY 



236 



concluded which of the three is the most toxic. Comparison of the 

 individuals of the series leads to nothing decisive. The next table 

 shows that fluctuating differences occur. 



TABLE III 

 POTASSIUM 



Enzyme 0.05 per cent. Incubation 5 hours at 45 C. 



There seems to be some indication that lithium is more toxic than 

 sodium or potassium, but the difference is too insignificant for a conclu- 

 sion. In all the vials the unboiled solutions were free from sediment. 

 Since the salt solutions themselves are neutral in all the concen- 

 trations tried, the column showing acidity of the reagent has been 

 omitted. The titration with the w/40 KOH instead of the w/20 KOH 

 used in the previous investigation with ethyl butyrate perhaps brings 

 out greater variations. The acidity of the control is usually with each 

 of these salts about the same in all concentrations and just about what 

 the plain enzyme solution itself is. This confirms the observation 

 made in the work with ethyl butyrate that there is no positive sign of 

 any chemical action between the substance of the enzyme solution and 

 that of the toxic solution. 



In this test the two salts are neutral in all concentrations tried. 

 One drop of the w/40 KOH gives a deep purple with 4" of the salt 

 solution in any of the concentrations used in the test. The unboiled 

 preparations were all free from sediment after incubation. Total inhi- 



