NATURAL HISTORY. 205 



&quot; The name of reason she obtains hy this : 

 But when by reason she the truth has found, 

 And standeth fixed, the Understanding is.&quot; DAVIES. 



Tht diffusion of an offensive smell by the pole-cat; 



The emission of a black fluid by the cuttle-fish ; 



The spiny hides of the hedge-hog and the porcupine, and the stinging hairs -which 

 envelope many caterpillars, are a few out of the innumerable instances of the 

 passive defences spoken of. 



But there is still another property which does not come under either of these 

 definitions, namely, the astonishing vitality possessed by such beings as are most 

 exposed to injuries, and by which life is not only supported without food for an 

 amazing length of time, but dislocated portions grow and become new animals. 



617. Why have quadruped* feet of small dimensions in 

 comparison with their bodies ? 



Because when an animal is supported on four feet, the extent of 

 its base of sustentation, and therefore its stability, cannot be 

 augmented in a sensible degree by extending the magnitude of 

 the feet. In fact, to have done so would have increased their 

 weight and diminished their speed and activity, without 

 conferring upon them any counteracting advantage. The Creator, 

 therefore, while he gave bipeds stability by making them walk 

 on the soles of their feet, gave quadrupeds lightness and 

 swiftness by causing them to walk on their toes. 



618. What is the difference between reason and instinct? 



Reason means the comparison of one thing with another ; and 

 in its more general sense, as applicable to the thoughts and 

 conduct of man, it means the comparison of that which he purposes 

 to do, with that experience in the past, either felt in himself or 

 learned from others, and the result of which comparison is to be 

 the guide of his actions. 



Instinct, though possessed by man up to a certain point, is the 

 proper badge and characteristic of the lower animals. Taken in 

 its general sense, it means the capacity which is within ; win h 

 borrows nothing from comparison and cannot piotifc by experience ; 

 but acts from the impulse of perfect objects on its organs of sense ; 

 also is indifferent to, and ignorant oij the past and the future. 



