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THE AMERICAN NATURALIST [Vol. XLIV 



placing the organism in a pertain direction with reference 

 to the direction of the stimulus. 



The term f right-movement or shock-movement or re- 

 coil (or a still better one) may be used to describe those 

 responses due to a sudden change in the environment. 

 Some of these shock-movements are doubtless tropisms, 

 but perhaps not all. These are the movements that are 

 due to differential sensibility ( Imtorschiedungsemp- 

 findung) in the sense of Loeb, and to transition stimula- 

 tion (Uebergangsreizung) in the sense of Pfeffer. 



There might also be some designation for the series of 

 responses which Jennings attempted to name as ''trial 

 and error," a complex of tropisms and shock-movements, 

 influenced by a varying physiological state. 



Very recently Bohn has proposed to account for all 

 behavior of lower organisms under four designations: 

 mechanical reflexes (tropisms), vital rhythms (a group 

 of autonomous movements of the botanists), differential 

 sensibility and associative phenomena. 



The ideas contained in these terms are all illustrated 

 by plant behavior. But the terms are inadequate, for 

 they are not coordinate. Some of them refer to re- 

 sponses, seme to physiological state. 



Before closing, reference might be made to Semon's 

 book, "Die Mneme," the ideas in which, especially re- 

 garding associative phenomena in behavior, aid one in 

 gaining a possibly clearer conception of the origin of 

 some reactions of organisms. 



Besides the reactions treated in the foregoing pages, 

 for which a harmony has been attempted between the 

 students of plant and animal behavior, we all know that 

 there are groups which need a better and more expressive 

 terminology than now is in use. As an illustration of 

 phenomena needing more precise terminology, I might 

 refer to the reactions known as opinasty and liyponasty. 

 A very complete and apparently adequate terminology 

 for all sensitive, non-nervous, reactions is given by Mas 

 sart in Annates de Vlnstitut Pasteur, 11)01, and atransla 

 tion of the same in Biologischem Ceutralhlatt, 22, 1902, < 



