140 



FRANK R. LILLIE. 



The effect of mercuric chloride (HgC^) on fertilization is 

 pronounced, but it is very different from that of copper chloride: 

 the initial stages of fertilization are relatively little affected, 

 and the susceptibility increases as fertilization progresses; fer- 

 tilized eggs show the effects much more rapidly than unfertilized. 

 Mercury also suppresses the movements of the spermatozoa at 

 great dilution, and offers in this way another contrast to copper. 



Table VII. records an experiment in which eggs were insemi- 

 nated in various dilutions of HgC^ in sea-water, between one 

 part in 1,250,000 and one part in 15,625. Most of the eggs 

 form fertilization membranes in the four lowest concentrations. 

 But the eggs do not segment, except at the lowest concentration 

 tested, and then only 20 per cent, irregularly. The fertilized 

 eggs cytolyze more rapidly than the unfertilized. 



EXPERIMENT 31 A. 



TABLE VI I 



EGGS INSEMINATED IN SERIES OF HgCh SOLUTIONS IN SEA- 

 WATER. (One drop of i : 25 : 7.5 c.c.) 



It was also observed that unfertilized eggs form membranes 

 in solution 5 (Table VII.) beginning at about five minutes. 

 When transferred to sea-water such eggs undergo changes 

 similar to eggs treated with butyric acid. 



