564 



CELL DIVISION IN EGGS OF CREPIDULA. 



IV. Effects of Electric Current. — (Continued.) 

 2. Graphite-Plate Electrodes. 



No. 



Stage. 



Strength. 



Duration. 



Normal. 



Results. 



1,106 



1-8 ceUs. 



5 mil. amp. 



5 min. 



17hrs. 



Normal eggs 24-40 cell stage; abnormal 1-4 cell 

 stages. Spindles gone, chromosomes fused, 

 polarity changed; polyasters and multiple 

 nuclei; cleavage irregular. Figs. 82-84. 



1,107 



1-8 cells. 



5 mil. amp. 



5min. 



25hrs. 



Similar to preceding; many eggs fragmented. 



1,108 



1-8 cells. 



5 mil. amp. 



5 min. 



60hrs. 



Normal eggs in early gastrula; others frag- 

 mented. 

 52-70 cells; many broken eggs, some polyasters 



1,109 



1-8 cells. 



5 mil. amp. 



2 min. 



30 hrs. 













and massed chromatin. 



1,110 (1) 



1-20 cells. 



5 mil. amp. 



2 min. 



4hrs. 



Many normal; few show effects of pressure; 

 others effects of convection in dislocation of 

 cytoplasm, nuclei, spindles, and in fusion of 

 chromosomes. 



(2) 



1-20 cells. 



5 mil. amp. 



2 min. 



22 hrs. 



Similar to preceding. Fig. 78. 



1,111 



1st matura- 

 tion to 4 

 cells. 



5 mil. amp. 



1 min. 



Ohrs. 



Identically like control. 



1,112 (1) 



1-8 cells. 



5 mil. amp. 



1 min. 



4 hrs. 



Chiefly normal; a few show effects of cur- 

 rent. 

 Chiefly normal 29-52 cells; a few show effects 



(2) 



1-8 cells. 



5 mil. amp. 



lmin. 



22 hrs. 













of _ convection in dislocation of parts, faint 













spindles and fused chromosomes. 



1,113 (1) 



1-8 cells. 



5 mil. amp. 



1 min. 



30 hrs. 



Many normal 52-70 cells; other 1-8 cells, show 

 effects of current. 



(2) 



1-8 cells. 



5 mil. amp. 



1 min. 



60 hrs. 



80-100 cells; similar to preceding. 



1,114 



Before matu- 

 ration. 



2 mil. amp. 



15 min. 



5 hrs. 



Few eggs and deeply stained; some show effects 

 of current in dislocation of parts. 



1,115 



1st matura- 

 tion. 



2 mil. amp. 



15 min. 



5 hrs. 



Many killed; a few show effects of current in 

 dissolution of chromosomes and spindles. 



1,116 



20-30 cells. 



2 mil. amp. 



10 min. 



5 hrs. 



Many killed; others show framboisia. 



1,117 



1-16 cells. 



2 mil. amp. 



5 min. 



3 hrs. 



Many eggs fragmented; a few show dislocation 

 of parts; polyasters and irregular cleavage. 



1,118 



1-20 ceUs. 



2 mil. amp. 



5 min. 



3Jhrs. 



Some show exovates, effects of pressure; others, 

 the effects of convection in dislocation of 

 nuclei and cytoplasm. 



1,119 



2-20 cells. 



2 mil. amp. 



5 min. 



20 hrs. 



Framboisia, scattered blastomeres; many dead. 



1,121 (1) 



1-2 cells. 



5 mil. amp. 



10 min. 



Ohrs. 



Nearly normal; a few tetrasters. 



(2) 



1-2 cells. 



5 mil. amp. 



10 min. 



31 hrs. 



Cleavage stopped in most eggs; tetrasters; 

 spindles displaced and chromatin dissolved. 

 Figs. 69-75, 87, 90, 92. 



(3) 



1-2 cells. 



5 mil. amp. 



10 min. 



16 hrs. 



Many abnormal cleavages due to pressure; 

 multiple nuclei; eggs without chromatin have 

 disintegrated. Fig. 79. 



(4) 



1-2 cells end 



:ontrol. 





16 hrs. 



Normal 24-32 cell stage. 



1,122 (1) 



1st matura- 

 tion. 



7 mil. amp. 



5 min. 



Ohrs. 



Eggs and spindles normal ; graphite plates were 

 probably in contact. 



(2) 



1st matura- 

 tion.* 



1st matura- 

 tion* 



1st cleavage. 



7 mil. amp. 



5 min. 



lhr. 



Normal second maturation. 



(3) 



7 mil. amp. 



5 min. 



3 hrs. 



Prophase first cleavage, normal. 



1,123 



7 mil. amp. 



5 min. 



Ohrs. 



Normal; graphite plates were probably in 













contact. 



1,140 (1) 



1 cell.* 



2 mil. amp. 



2 min. 



5J hrs. 



Fig. 86. Many eggs normal; others have poly- 

 asters and multiple nuclei. Some show effects 

 of pressure, others of electric current; in 

 latter nuclear membrane, chromatin, and 

 spindle fibers almost dissolved; chromosomes 

 do not dissolve as readily as resting chro- 

 matin; in a few cases nuclei and cytoplasm 

 dislocated, probably by current. 



(2) 



1 cell.* 



2 mil. amp. 



2 min. 



11 hrs. 



Similar to preceding. 



