ACTIVATION OF STARFISH EGGS BY BUTYRIC ACID. 



posure with rise of temperature, and the tendency to a shortening 

 of the reaction-time as the season advances, are both shown 

 clearly. The date of each experiment is given, and each lot of 

 eggs is designated by number so as to render possible comparison 

 between different lots. It will be noted that in general the tem- 

 perature-coefficients between 8 and 18 are of the usual order 

 of chemical reaction-velocities, but that above 18 they increase 

 rapidly. The significance of this increase has already been 

 considered. 



(6) Experiments at Temperatures Below 8. 



In these experiments the sea-water and solutions used were 

 first cooled at the required temperature, and then added to the 

 beakers containing the eggs as before. The temperatures were 

 kept constant during the period of the experiment by immersing 

 the beakers in battery-jars containing cold water, together with a 

 sufficient quantity of chopped ice to keep the temperature at the 

 desired point. With proper care the fluctuations of temperature 

 are slight under these conditions usually less than a degree on 

 either side of the temperature chosen, an approximation sufficient 

 for the purpose of these experiments. 



Table V gives the results of three series of experiments with 

 a single lot of eggs at 2, 4, and 6. The eggs were placed, 

 shortly before the separation of the first polar body, in the solu- 

 tion of butyric acid (.006 n in sea-water) at the three temperatures, 

 and portions were returned to normal sea-water at room tem- 

 perature after exposures varying from 5-65 minutes. 



TABLE V. 



JUNE 13, 1916. EGGS FROM Two STARFISH. CONTROLS SHOW NORMAL MATURATION AND 

 NORMAL DEVELOPMENT AFTER FERTILIZATION. 



With exposures of 35 minutes and longer a large proportion of the eggs undergo 

 complete cytolysis ("ghosts" next day), especially in Series A (A > B > C). 



