SENSORY STIMULATION OF THE OYSTER, OSTREA VIRGINICA, BY CHEMICALS 253 
and it was thought to be peculiar to this salt. However, it has been found to be pos- 
sible with other salts as well. In Figures 5 and 6 the results of one series of tests with 
Figure 3. — Average latent period values (ordinates) of the 
reaction of the oyster to different concentrations (abcissae) 
of sodium chloride. Two series of experiments made under 
different conditions are given. (See fig. 4) 
Figure 4.— Data given in Figure 3 plotted as logarithmic 
reciprocal of latent period and logarithmic concentration 
Figure 5.— Curve showing two different latent period levels 
in the response of a single specimen to magnesium chloride. 
The points represent averages. (See fig. 6) 
Figure 6.— Logarithmic presentation of data given in Fig- 
ure 5 showing relation between logarithmic concentration 
and logarithmic reciprocal of latent period 
MgCl 2 are given. The points fall clearly into two approximately parallel curves 
about one second apart. 
The two curves are mathematically comparable. Further experiments are in 
progress for the purpose of finding the significance of this behavior. 
