564 



CELL DIVISION IN EGGS OF CREPIDULA 



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



2. Graphite-Plate Electrodes. 



No. 



Stage. 



1,106 



1-8 cells. 



Strength. 



mil. amp 



Duration. 



1,107 

 1,108 



1,109 

 1,110 (1) 



1-8 cells. 

 1-8 cells. 



1-8 cells. 

 1-20 cells. 



mil. amp 

 mil. amp 



mil. amp 



mil. amp 





1,111 



(2) 



1,U2 (1) 



(2) 



1-20 cells. 

 1st matura- 

 tion to 4 



cells. 

 1-8 cells. 



1-8 cells. 



mil 



amp 



1,113 (1) 



mil. amp 

 mil. amp 



1-8 cells. 



1,114 



1,115 



1,116 

 1,117 



1,118 



(2) 



1-8 cells. 



Before matu- 

 ration. 



1st matura- 

 tion. 

 20-30 cells. 



1-16 cells. 



1,119 

 1,121 (1) 



(2) 



1-20 cells. 



(3) 



2-20 cells. 

 1-2 cells. 

 1-2 cells. 



mil. amp. 



mil. amp. 

 mil. amp. 



mil. amp. 



mil. amp. 

 mil. amp, 



mil. amp 



mil. amp 

 mil. amp 

 mil. amp 



1-2 cells. 



mil. am 



122 (1) 

 (2) 



(4) 1-2 cells end control. 



(3) 





1,123 



1st matura- 

 tion. 



1st matura- 

 tion.* 



1st matura 

 tion.* 



1st cleavage. 



mil. amp 

 mil. amp 



mil. amp 



mm 



mm 



5 min. 



Normal 



hrs 



Results. 



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

 stages. Spindles gone, chromosomes fused 

 polarity changed; polyast 





hrs 



hrs 



mm 



mm 



hrs 



Similar to preceding; many 

 Normal 



and multiple 

 Figs. 82-84. 



fragmented 



4 hrs. 



mm 

 min 



hrs 

 hrs 



eggs in early gastrula; others frag- 

 mented. 



52-70 cells ; many broken eggs, some polyasters 

 and massed chromatin. 



Many normal; few show effects of pressure; 

 others effects of convection in dislocation of 

 cytoplasm, nuclei, Bpindles, and in fusion of 

 chromosomes. 



Similar to preceding. Fig. 78. 



Identically like control. 



mm 



hrs 



mm 



hrs 



normal: a few show effects of cur- 



rent. 



mm 



normal 29-52 



hrs 





and fused chromosomes 



parts 



nun 

 min 



mm 



60 hrs 

 5 hrs 



min 



min 



hrs 



Many normal 52-70 cells ; other 1-! 



effects of current. 

 80-100 cells; similar to preceding. 

 ^ew eggs and deeply stained ; some 



of current in dislocation of parts. 



-* * ^ * * 4* i 1^ _- _ L n> ^- 



5 hrs 

 3 hrs 



Many killed 



chromosomes and spindles 



Many killed ; others show f ramboisi 



min 



Many eggs fragmented 



irregul 



3£hrs 







mm 

 min 

 min 



lOhrs 

 Ohrs 



3J 



tetrastere 



min 



16 hrs 



mm 



1 6 hrs 

 Ohrs 



Some show exovates, effects of pressure; otners, 

 the effects of convection in dislocation ot 



nuclei and cytoplasm. , , 



Framboisia, scattered blastomeres; many dead. 

 Nearly normal ; a few tetrasters. 



a S3E. tsTacedUfhroS dissolved 



*£? * a^ormil' cleavages due to pressu* 

 multiple nuclei ; eggs without chromatin hav, 

 disintegrated. Fig. 79. 



Normal 24r-32 ceU stage. 



Eggs and spindles normal ; graphite plates wer 



min 



mil. am 



min 



mm 



1,140 (1) 



1 cell. 



mil. am 



mm 



lhr. 

 3 hrs 

 Ohrs 



in 



5£ hrs 





(2) 



lcell. 



mil. amp 



probably in contact. 

 Normal second maturation. 



Prophase first cleavage, normal. 



Normal; graphite plates were 



probably 



of 



membrane 



min 



pressure, 

 latter nuclear mem^^, -— , mosom es 

 ndle fibers almost dissolved , ^gj" chl0 . 



not dissolve as readily as n r « s ^ plasm 

 Ltin : in a few cases nuclei and cytopia* 



current 



hrs 



preceding 



