282 BEHAVIOR OF THE LOWER ORGANISMS 



rable to the atom in physics. To obtain such a unit it is necessary to take 

 into consideration as an additional possible variable, the physiological 

 state of the organism. Dr. E. G. Spaulding has suggested the follow- 

 ing: We cannot properly say for a given organism "same stimulus, 

 same reaction," as appears to be the usual idea of a reflex. On the 

 other hand we can say "same physiological state, same stimulus, same 

 reaction," and this supplies whatever need there may be for a simple 

 invariable element of behavior. To this element the term "reflex" or 

 an equivalent one might be applied, and we might then maintain that 

 the behavior of all organisms is made up of reflexes. But on this defi- 

 nition the question whether the behavior of a given organism is made 

 up of reflexes is not a problem for objective investigation; but the con- 

 ception that it is thus made up is a postulate, in accordance with 

 which we interpret the results of our observations ; and this applies to 

 the highest as well as to the lowest organisms. The assumption that 

 varied physiological states exist is of course one of these interpretations, 

 made to save what is essentially this very postulate, — the principle 

 that like causes always produce like effects. 



LITERATURE XV 

 Reflexes and Behavior 



Hobhouse, 1 901 ; James, 190 1 ; Beer, Bethe, and v. Uexkull, 1899; Titch- 

 ener, 1902; Driesch, 1903; v. Uexkull, 1897. 



