PREFACE vii 
endeavoured to show that this view is erroneous and that 
both are nourished similarly. 
T have also tried to show that the sensitiveness of the 
plant and the animal is alike in properties, though differ- 
ences are apparent in the direction of its differentiation. 
I have avoided as far as possible the discussion of con- 
troverted points, feeling that this would be out of place in 
a work intended to serve as an introduction to the subject. 
Such matters are more properly treated of in the more 
comprehensive works to which I have already alluded. 
J. REYNOLDS GREEN. 
CAMBRIDGE. 
