306 SCIENCE PROGRESS. 



more than the medium in which the nucleus lives, and 

 through which it exhibits its powers. The nucleus may 

 move about in the mass, acquiring ' spheres of influence ' 

 at its halting places, and so producing the vital phenomena. 

 It is the nucleus which is the vital unit, and there is no 

 bond between nucleus and cytoplasm which shall compel 

 us to regard their union as the necessary condition of living 

 individuality." 



I have made use of my own expressions, but if this is not 

 the plain meaning of the short editorial entitled "The 

 Reign of the Nucleus" in the January number of Natural 

 Science, what is ? 



The writer of the editorial is so captivated with the pros- 

 pect opened up by his interpretation — a perfectly legitimate 

 interpretation — of Mr. Sedgwick's writings, that he forthwith 

 abolishes the existence of cells altogether and talks glibly 

 of " protoplasmic masses," ignoring the fact that the masses 

 in question are divided up into corpuscles. Following up 

 his theme of protoplasmic masses dominated by nuclei, he 

 lightly dismisses the arguments which I put forward, 

 saying that the segmentations of Nereis, Unio, etc., exhibit 

 nuclear lineage rather than cell lineage (who could 

 hold such an opinion after a careful study of Wilson and 

 Lillie's figures ?), and winds up with the following astonish- 

 ing piece of criticism : " In drawing an argument for the 

 cell-theory from the definite places assigned to cells in 

 development Bourne seems to us to have overlooked the 

 experiments of Wilson, Driesch and Hertwig, who have 

 shown that the nuclei may be moved about in the proto- 

 plasmic mass almost as freely as a ' heap of billiard balls 

 may roll over each other ' ". I rubbed my eyes and 

 wondered. I thought I knew the works of Driesch, 

 Hertwig and Wilson pretty well, and that I had considered 

 them carefully, and I had certainly regarded them as strong 

 evidence in favour of the cell-theory as I conceived of it. 

 A short search soon hit upon the passages which are 

 professedly quoted. First for Driesch : x " Die Furchungs- 



1 Hans Driesch, Entwicklungmechanischse Studien, iv., Zeitschrift fUr 

 IViss. Zoologie, vol. Iv., 1893. 



