272 



LEIGH HOADLEY. 



lots of eggs, under different conditions, and are therefore not as 

 suitable for comparison as they would be had they all been done 

 simultaneously with one set of eggs. Three sets of experiments 

 were therefore set up for the purpose of comparison. 



The experiment which appears in Table Vila, was made to 



Table Vila. 



Comparative test with membrane inhibitory concentrations. July 15, 1922 

 Experiment 10 : 15 A.M. Temperature 21 C. Sperm and eggs fresh. Insemina- 

 tion 1 : 25 : 7.5. Membranes formed well, save in immediate inseminations. 



1 In the above experiment, the results for Au and Cu are interpolated. 



show the effect of the various solutions on the viability of the 

 same lot of eggs under the same conditions. In each case the 

 concentration used is that of membrane-inhibition. In this table 

 it will be noted that only the figures for the first cleavage are 

 given. In all save the immediate inseminations, membranes 

 were present on a high percentage of the eggs. The table, 

 therefore, emphasizes the great difference between the inhibition 

 of initial and subsequent events, and shows the great similarity 

 of the action of all of the salts. In this table, the figures for 

 AuCl 3 and CuCl 2 are interpolated. It was found, however, that 

 both of these membrane-inhibiting concentrations proved more 

 toxic to cleavage than those of the other salts. I have not used 

 HgCl 2 in this test as it shows no membrane-inhibiting point. 



The experiment summarized in Table VI lb was performed to 

 determine the time when superficial cytolysis first begins to 

 appear in uninseminated eggs placed in membrane-inhibiting 



