412 BIOLOGY FOR BEGINNERS 



2. Involuntary and unconscious action of internal organs con- 

 trolled by medulla and sympathetic system. 



3. Involuntary but conscious reflex actions controlled by the 

 spinal cord. 



4. Actions, at first voluntary, that have become reflex (auto- 

 matic) by habit, like learning to walk. 



Habit Formation. To accomplish a given act or thought, the 

 nerve impulse has to connect up various parts of the brain. At 

 first this is done with difficulty and we say we are " learning to 

 read " or to ride a bicycle or play a piano. However, repeated 

 voluntary acts soon make their proper nerve connections easier,, 

 as if a path were being worn in the brain along which the impulses 

 travel with greater and greater ease. 



If we continue doing a certain act or thinking a certain way often 

 enough, it becomes the easiest way to act or to think, and we say 

 we have " acquired the habit." If we look up the derivation of 

 that word, habit, we find that it comes from " habeo," meaning to 

 have or hold. So instead of our getting the habit, as we say, the 

 habit has " got "us. 



It is a serious thing to think of, for our whole life is a complex 

 mass of habits, things which hold us, acts and thoughts that 

 do themselves, and which we " just can't help." How careful we 

 should be that those brain paths are the best arranged so that 

 habits of thought shall be prompt and accurate. How watchful 

 we should be that only good and helpful paths be followed, for, 

 whether we wish it or not, the habit will get and hold us. It is only 

 too true that " As a man thinketh . . . so is he." 



" The hell to be endured hereafter, of which theology tells, is 

 no worse than the hell we make for ourselves in this world by 

 habitually fashioning our characters in the wrong way. Could 

 the young but realize how soon they will become mere walking 

 bundles of habits, they would give more heed to their conduct 

 while in the plastic state. We are spinning our own fates, good or 

 evil, and never to be undone. Every smallest stroke of virtue or 

 of vice leaves its never-so-little scar. The drunken Rip Van Winkle, 

 in Jefferson's play, excuses himself for every fresh dereliction by 



