exhibited by Turgescent Pith in water . 125 
It is probable that by the study of other tissues, especially 
those of roots, the series between the Sunflower pith and the 
contracting root-tissues of De Vries* experiments might be 
made even more complete. But enough has been done to 
fully confirm that naturalist’s view of the question. 
Botanic Garden Laboratory, Cambridge. 
