68 THE VITAL FUNCTIONS. 



the greatest and most permanent good. There 

 can be no doubt that the scheme, by which one 

 animal is made directly conducive to the sub- 

 sistence of another, leads to the extension of 

 the benefits of existence to an infinitely greater 

 number of beings than could otherwise have en- 

 joyed them. This system, besides, is the spring 

 of motion and activity in every part of nature. 

 While the pursuit of its prey forms the occupa- 

 tion, and constitutes the pleasure of a considerable 

 part of the animal creation, the employment of 

 the means they possess of defence, of flight, and 

 of precaution is also the business of a still larger 

 part. These means are, in a great proportion of 

 instances, successful ; for wherever nature has 

 inspired sagacity in the perception of danger, she 

 has generally bestowed a proportionate degree of 

 ingenuity in devising the means of safety. Some 

 are taught to deceive the enemy, and to employ 

 stratagem where force or swiftness would have 

 been unavailing : many insects, when in danger, 

 counterfeit death to avoid destruction ; others, 

 among the myriapoda, fold themselves into the 

 smallest possible compass, so as to escape detec- 

 tion. The tortoise, as we have already seen, 

 retreats within its shell, as within a fortress ; the 

 hedge-hog rolls itself into a ball, presenting 

 bristles on every side ; the diodon inflates its 

 globular body for the same purpose, and floats 

 on the sea, armed at all the points of its surface ; 



