Successive stages of nuclear division seen in one living amceba which was stained by 

 the jelly method when actually alive and about to divide. The nucleus only is repre- 

 sented ; it was drawn from life by the camera-lucida. Amoebae differ from any other cells 

 yet tested in that they will continue to live for a few minutes with the nuclear chromatin 

 stained. It is believed that these figures are the first that have been seen of a nucleus of 

 a living cell passing through the stages of division with the parts stained artificially. 



The amceba came from a strain different to A. ottrea ; it has a coefficient of diffusion 

 of about 16, and seems more resistant to stain. It had been growing on jelly containing 

 the auxetic tyrosine, and it was immediately after its transference from that jelly to one 

 containing stain (polychrome methylene blue) that these figures were seen. The blue 

 coloration of the spindle is exaggerated in the drawing ; in the living cell it was very faint. 



Frontispiece 



