whole animal race, with of course difference of degree, 

 we may express by the term docility, meaning by it the 

 power of making acquisitions of every kind independent 

 of the native or inborn capacities. There is evidently a 

 great inferiority in the extent and in the character of the 

 brute acquisitions as compared with humanity. It is 

 doubtful how far an ordinary quadruped can revive the 

 pictorial impressions of sight in the entire absence of the 

 original so as to go through an operation truly mental, 

 and live in the past, the present and the future. The 

 best of animals can go but a little way towards recogniz- 

 ing the proportions of natural objects, chiefly on account 

 of their utter want of all the artifices of indirect vision, 

 which have their perfect exemplification in the human 

 sciences. 



It usually happens that every active weapon or instru- 

 ment belonging to the structure of an animal is fully pro- 

 vided with nervous communications with all the other 

 parts of the system through the common centre of ner- 

 vous action, and is in this way put to employment on all 

 convenient occasions. Nothing more is required than 

 such a method of connection to insure the application of 

 every species of active impulse wherever it can be of any 

 avail. The electric organs of the torpedo are related by 

 massive cords of nerve to the brain of the animal, and 

 act in sympathy with its wishes and movements. 



We are to conceive of each class of animals as pos- 

 sessed of a certain number of susceptibilities and active 

 capacities in more or less measure of energy, and also of 

 the power of harmonizing, combining and arranging the 

 one to meet the other through the medium of a central 

 brain, and as having this power in unequal degrees. 



The varieties of the sense of hearing furnish a basis of 

 discrimination of the animal species. This sense is, per- 



