108 



GARY N. CALKINS 



13 



B' 



14 



Fig. 13 Experiment 72. Cell cut at the mid-phase of division. B divided in the 

 original plane into B and B' . A formed a single perfect cell but without micronu- 



cleus. ^^ 



Fig. 14 Experiment 69. Cell cut at the mid-phase of division. A, B' and B 

 on right show the results after 24 hours, B having divided into B' and B". A shows 

 the typical nuclear features of a cell just after division, but has no micronucleus. 



