REFLEXES IN BEHAVIOR 281 



stimulus are sufficient to account for their behavior, without the neces- 

 sary intervention of consciousness. This is well expressed by v. Uexkiill 

 (1897, p. 306) when he says that we are to regard the reflex as "the 

 necessary course of a process that is conditioned by nothing else than 

 the mechanical structure of the organism." Shall we include the phys- 

 iological state of the organism as part of its mechanical structure? If 

 we answer this question in the negative, then it is clear that the behavior 

 of the lower organisms is not reflex in character. If on the other hand 

 we answer this question in the affirmative, holding that the physiological 

 state is some chemical or physical configuration of the substance of the 

 organism, and therefore to be included in its mechanical structure, then 

 the entire question concerning the reflex character of behavior in a given 

 organism loses its objective character and evaporates into thin air. For 

 in the highest as well as the lowest organism the reactions must be sup- 

 posed to depend upon the physical and chemical constitution of the 

 organism, unless we are to accept vitalism. And if when we say that 

 the behavior of an organism is reflex in character, we mean only that 

 its behavior depends upon its physical and chemical make-up, we can 

 make no distinction upon this ground between the behavior of lower 

 and higher organisms. This point is indeed well recognized by thought- 

 ful psychologists. "The conception of all action as conforming to this 

 [the reflex] type is the fundamental conception of modern nerve physi- 

 ology," says James ("Principles of Psychology," Vol. I, p. 23). Those 

 who have been most strenuous in attempting to demonstrate that the 

 behavior of certain lower organisms is "purely reflex" in character would 

 probably be the last to hold that in the higher organisms behavior must 

 be explained on essentially different principles. The attempt often 

 made to contrast the behavior of lower organisms as reflex with that 

 of higher organisms as something else, seems therefore a shortsighted 

 and pointless proceeding. What a given organism does under stimu- 

 lation is limited by its action system, and within these limits is deter- 

 mined largely by its physiological condition at the time stimulation 

 occurs. In the lowest organism the action system confines the varia- 

 tions in behavior within rather narrow limits, and the different physio- 

 logical conditions distinguishable are few in number ; hence the behavior, 

 is less varied than in higher animals. But the difference is one of degree, 

 not of kind. The behavior of Paramecium and the sea urchin is reflex 

 if the behavior of the dog and of man is reflex ; objective evidence does 

 not indicate that there is from this point of view any fundamental differ- 

 ence in the cases. 



The importance attributed to the concept of reflex action is of course 

 due to the desire to find a simple invariable unit for behavior, compa- 



