222 The Unity of the Orgamism 



recur to the chapter on tropistic activities and their an- 

 atomical groundwork, recalHng that it was the special aim 

 of our discussion to show the inevitable organismal trend of 

 the whole doctrine of tropisms. It should be remembered 

 also that trojjisms are, all of them, probably, beyond ques- 

 tion adaptive in fundamental nature; i.e., they work in the 

 interest of either the individual as a whole or of the species 

 to which the individual belongs. The circumstance that 

 under occasional more or less artificial conditions the ac- 

 tivities of an animal may result in injury to it or even in its 

 death, is not proof that on the whole those activities are not 

 advantageous. A horse or man may make himself sick now 

 and then by taking the wrong kind of food or too much 

 food, but this does not prove eating to be useless on the 

 whole, or non-adaptive. 



Another important thing to bear in mind about tropisms 

 is their automaticity, or preferably their intrinsicality. 

 They are rooted in and partake of the very essence of the or- 

 ganism — so much so that they manifest themselves inevitably 

 when the right external and internal conditions are present, 

 whether the general ends which they normally serve are at- 

 tained in the particular instance or not. The flight of the 

 moth toward the flame, even at the sacrifice of its life some- 

 times, is a manifestation of a tendency that works, on the 

 whole, for the good of the animal. That the moth follows 

 the impulse even to death merely shows how tremendously 

 deep-seated this type of reaction is. That the activity may 

 result in injury or death in a special case is just because the 

 case is special, i.e., it is a departure from the regular con- 

 ditions under which the reaction-type became incorporated 

 in the organization of the creature. Being always poised 

 for a particular kind of action, and having a supply of en- 

 ergy to execute the action, are unquestionably among the 

 most distinctive attributes of animal organisms. Such or- 

 ganisms are distinguished from plant organisms not only 



