362 



A. RICHARDS. 



tage gained in the early stages sometimes takes expression in more 

 vigorous larvae rather than in more rapidly developing larvse. In 

 some experiments, indeed, hatching seems actually to be delayed 

 by the treatment. A summary of the experiment numbered 156 

 is here given as an example of the sodium hydrate effect. Many 

 other experiments were performed to verify these points, but they 

 need not be given here. 



EXPERIMENT No. 156. JULY 26, 1921. BEGAN AT 6:50 A.M. EGGS IN -J-CELL 



STAGE. 



7/29, 10:00 A.M. 



156.1 Larva large, moderately active. 



156.2 Larva active, rotating. 



156.3 Larva active, healthy. 



156.4 Larva active, rotating. 



156.5 Dead. 



The effect of ammonium hydroxide is seen in experiment 159, 

 for example. Here, too, the acceleration is evident. It is a little 

 more difficult to obtain accurate results with ammonia since the 







concentration of the solution changes. I think, however, that the 

 effects are not different in character from those of the sodium 

 hydrate, although they are perhaps less evident in this case. 



EXPERIMENT No. 159. JULY 31, 1921. BEGAN AT 7:10 EGGS JUST COM- 



PLETED 3RD- DIVISION. 



