II. THE PLACE OF PLANT RESPONSES I X T 1 1 E 

 CATEGORIES OF SENSITIVE REACTIONS 



PROFESSOR FREDERICK C. XEWCOMHE 

 University of Michigan 



More than two decades ago in the hands of Darwin, 

 Sachs, Wiesner, Pfeffer, Strasburger, Stahl and others, 

 the principal sensitive reactions for both fixed and free- 

 moving plants had been determined. At that period, in 

 animal biology only a few scattered papers had appeared 

 on sensitive reactions. The zoologists approached this 

 study through human psychology; starting with intelli- 

 gence and reflexes in the highest animals, they cast a 

 glance now and then toward the lower metazoa, and 

 talked of reflexes and instinct. Plants, not standing in 

 the line of descent which has its climax in man, were 

 studied in an objective manner with no attempt to bring 

 their reactions into a scheme of comparative psychology. 



For the past two decades more attention has been paid 

 to the study of behavior in the lowest animals, with the 

 result that a great body of literature has already arisen, 

 some of it tainted with anthropomorphism, but the most 

 of it describing simply ami carefully the reactions of the 

 protozoa and the lower metazoa. 



This independent activity on the part of the plant and 

 animal biologists has resulted in the upbuilding of t" 

 almost independent bodies of literature on the behavior 

 lower organisms. Such early workers in the field as Ver- 

 worn and Loeb compared and identified the reactions 

 which they saw in the lower animals with those already 

 published for plants; but as the zoologists have worked 

 on, and more workers have come into the field, there has 



