7O THE METHOD OF DARWIN. 



ture was not due to sensitiveness, but to the 

 action of the shellac by means of which the 

 objects had been attached. Microscopic exam- 

 ination of radicles to which the materials used 

 for attachment had been applied showed that 

 the cells were affected. In short, the curvature 

 of radicles ascribed to sensitiveness to touch 

 has been shown to be due to pathological con- 

 ditions brought into existence by the experi- 

 ments themselves. The reasoning was correct 

 enough, but the premises were false. Initial 

 errors led to a false conclusion, but the experi- 

 ments were all valuable as starting points for 

 more searching investigations. The hypothesis 

 of sensitiveness has been proved by Wiesner 1 

 and others to be untenable, but much more is 

 known of the Darwinian curvature now than 

 when the Darwins published their conclusions. 

 All Darwin's works on plants furnish ex- 

 amples of the practically complete develop- 

 ment of the conditions of the problem. In 

 the opening of the chapter on " Illegitimate 

 Offspring of Heterostyled Plants," he said, "I 

 give the results of my experiments in detail, 

 partly because the observations are extremely 



1 Wiesner, J., Untersuchungen liber die Wachsthumsbewe- 

 gungen der Wurzeln (Darwinische und Geotropische Wurzel- 

 Kriimmung). Sitz. Akad. Wien, V. 89, I. pp. 223-302. 



