UTAH ACADEMY OF SCIENCES 163 
paper the writer has deduced an expression of the second 
degree which describes the progress of the disinfection of 
B. typhosus with 0.2 per cent phenol with considerably 
greater accuracy than does the expression for a reaction 
of the first order. This is shown in Table I below. In 
the third column are the values calculated by Lee and 
Gilbert for the constant, k, in the general expression for 
a monomolecular reaction. In the fourth column are the 
values for the constant, c, calculated from the equation 
deduced by the writer. In spite of the constancy of 
these last values, however, the writer does not believe 
that the expression from which they are calculated repre- 
sents the true course of the reaction. Rather, could the 
distribution frequencies of the micrcorganisms, in res- 
pect both of age and of resistance to the poison, be taken 
into account, it is not improbable that the course of dis- 
infection could be expressed by a simple linear equation 
of the first degree. This is indicated in some experiments 
made by the writer. | 
In the course of an extended investigation of marine 
wood borers the writer has collected many data bearing 
on the toxicities of a number of phenols for the small 
crustacean borer, Zimnoria. This form is admirably 
adapted for such experiments. The adults average 2.5 
mm. in length, and can be obtained in great numbers. 
In Zimnoria all the phenols investigated produced motor 
paralysis, the onset of which in any individual could be 
accurately noted. When paralyzed Limnoria are washed 
and returned to fresh sea-water, the return of motor 
activity is rather sharply defined, unless the animals are 
moribund. 
If, for a given poison, the values of r, the average 
time for beginning recovery, be plotted as ordinates 
against corresponding values of t, the time the animals 
are in the solution of the poison, a discontinuous curve 
is obtained. The first, short portion is presumed to cover 
the time taken for establishment of equilibrium of poison 
between the sea-water and the animals. The next por- 
tion of the curve, extending in a number of cases over a 
very considerable range of t, is a straight line. In one or 
two instances the curve becomes again discontinuous as 
