390 ROBBINS 



opment by minute amounts of specific substances, our increasing knowledge 

 of the structure of the cell and the changes which the nucleus and the cell 

 undergo in division and maturation, as well as new techniques such as 

 chromatography, electron microscopy, tagged atoms, tissue culture, and the 

 like, suggest that future progress in some of these fundamental areas may be 

 more rapid than we could have reasonably anticipated 20 or even 10 years 

 ago. 



