Solution Tension and Toxicity in Lipolysis. 265 
headed “M.” The column headed “Increase ” shows the difference 
between the acidities of the control and of the enzyme solution at 
the close of the incubation period, and expresses the activity of the 
enzyme under the conditions tested for the concentration of the 
corresponding toxic solution indicated in the column headed “ M.” 
If one drop of alkali produced a deep purple, the acidity was called 
zero, 
TABLE I. 
Sopium, LirHIUuM, AND POTASSIUM. 
M? Reagent.1 Control.t Enzyme.} Increase.t 
Water are 0.00 0.20 0.20 
64 0.00 0.00 0.20 0.20 
32 0.09 0.00 0.15 0.15 
16. 0.00 0.00 0.10 0.10 
8 0.00 0.00 0.07 0.07 
4 0.00 0.00 0.03 0.03 
Enzyme, 0.0125 per cent.!_ Incubation period, 4 hours. 40° C. 
This test was repeated the following day with exactly the same 
result, so that the relative toxicity of these three nitrates is based 
upon the agreement of six individuals for each concentration of the 
toxic salt both for the controls and for the enzyme. The salts were 
neutral in all concentrations tested. The controls were all neutral 
after incubation, so it is evident that the butyrate added to the 
control must have been neutral at the beginning and did not per- 
ceptibly become saponified. 
A concentration of M-4 does not totally inhibit, while in M-64 
there is no inhibition at all, as is shown by the figure, for the enzyme 
| in the absence of toxic agent. Since the same figures were obtained 
for all three salts in a contemporaneous test, it seems clear that they 
are practically equal in toxicity under the conditions tried. Since 
M—4 allows only 0.03, it is reasonably certain, though not proved, 
that M-2 is the approximate point of total inhibition. All the 
_ preparations were water clear after digestion and with no sediment 
ro whatever present; the end point was very sharp. 
_ Barium, strontium, and magnesium in contemporaneous test. — It may 
: be noted, by referring to Table I, that since all the controls were 
neutral and the reagents also neutral in the concentrations indicated, 
: the figures for the column headed “ Enzyme” are identical with the 
« 1 See pages 263 and 264. 
