364 



A. RICHARDS. 



these eggs, but the nature of the desiccated gland and the condi- 

 tions of the experiments do not lend themselves to an exact state- 

 ment of the effect itself or of the strength of material necessary 

 to produce it. It is to be regretted that there was no further 

 opportunity to study this matter in detail upon Haminea eggs. 



Finally, influenced by Mathews's finding that the development 

 of Astcrias larvse is hastened by pilocarpine hydrochlorate, the 

 writer investigated the effect of this reagent upon Haminea. 

 Mathews did not record any direct observations on the rate of 

 cleavage, although an acceleration is to be inferred from his gen- 

 eral results. The effect of pilocarpine on Haminea eggs was tried 

 on concentrations of .1 c.c., .2 c.c., .3 c.c., .4 c.c., and .5 c.c. of 

 y 2 per cent, solution in 10 c.c. sea water. It was found that for 

 these concentrations the effect, although slight, is an acceleration 

 in any one cleavage in proportion to the concentration. The effect 

 is less marked than in the case of the hydroxides of the first 

 periodic group. Experiments 1/2.1 and 172.4 will serve as ex- 

 amples of the effects of pilocarpine hydrochlorate treatment. 

 Pilocarpine nitrate was also tried, but the acceleration was not 

 obtained by its use. It is probable that it is only the hydrochlorate 

 which possesses the property of accelerating division rate. 



EXPERIMENT No. 172. AUGUST 16, 1921. BEGAN AT 6:35 A.M. EGGS JUST 



COMPLETED 2ND DIVISION- 



DISCUSSION. 



These experiments have raised a number of questions that the 

 writer was unable to investigate because of the shortness of time 

 at his disposal. In continuing the work it is necessary to use other 

 material than Haminea eggs, a condition which is to be regretted, 

 since these eggs are so favorable for this study. Work is never- 

 theless going on in this laboratory at the present time in an attempt 

 to extend and develop certain of these conclusions and to clear up 

 some of the questions. 



