REFLEX ACTION 53 



ing convulsion. Clearly, then, a certain degree of central 

 resistance is the most favorable condition for the activities 

 of life. Any increase will tend to prevent needed adapta- 

 tions to external changes, and any great decrease will make 

 the reflex responses exaggerated, disorderly, and ill suited 

 to their object. There is reason to suppose that the more 

 frequently occurring reflexes become easier of production 

 through a lowering of resistance in their particular path- 

 ways. This brings us close to the subject of habit for- 

 mation. 



Our emphasis has been constantly upon the advantage 

 derived by the animal (or by man) from the possession of 

 reflex capacities. When the environment is the accus- 

 tomed one and the changes taking place are such as the 

 species has often experienced, we find that almost every 

 reflex is obviously beneficial. The reactions are such as 

 maintain bodily equilibrium, secure nutriment, evade or 

 defeat enemies, resist changes of temperature, all making 

 for self-preservation. But it must be noted that an unin- 

 telligent mechanism will act amiss in any environment 

 which is sufficiently unlike the accustomed one. It will 

 hardly be claimed that the reflexes exhibited by the novice 

 on first going to sea help him in the struggle for existence. 

 A number of reflex effects can be thought of which can 

 scarcely be of value. Sneezing when going out into bright 

 sunlight is one of these. Hiccups following immoderate 

 laughter do not seem to be of any service, nor does laughter 

 itself when induced by tickling. These instances, which 

 on the whole have little importance, are mentioned simply 

 to enforce the contention that the reflex mechanism, how- 

 ever refined, is not directed in its routine performances 

 by intelligence. Its structure determines its conduct. The 

 finger laid upon hot iron is twitched away before the situa- 

 tion is reasoned out, in fact, before pain is felt. Central 

 connections exist which make the movement sure to occur. 

 If we could rearrange those central connections we can 

 conceive of a luckless subject who would not remove his 

 finger from the stove, but would stand violently coughing 

 while the injury proceeded. 



