Animal Intelligence. 861 



manufactured articles, made from other substances. A spider's web, 

 a bird's nest, a beaver's dam, a Hottentot's hut, a locomotive, are called 

 artificial works. They are articles of a foreign, non-vital character, pro- 

 duced by the action of certain organs called brain and muscles. They 

 are manufactured articles made from other substances. 



The action of the gland in the production of its secretions is auto- 

 matic, but so is the action of the brain, and either of them is set going 

 by the stimulation of a nerve current. It may be said that the activity 

 of the gland results in chemical, and that of the brain in mechanical 

 change. But there is good reason to believe that chemistry is only a 

 branch of mechanics. Since then the same mechanical agency operates 

 both the organs, and both are automatic ; their products must sustain 

 a common relationship to the rest of nature. They are equally natural ; 

 and we conclude that the so-called artificial work is a natural product, 

 art is a subdivision of nature, and reason a mode of motion. , 



CHAPTER LXXVII. 



ANIMAL INTELLIGENCE. 



In studying the comparative anatomy of the brain, we found a won- 

 derful correspondence running through the brains of all the vertebrates. 

 This correspondence is the more striking if the attention be confined to 

 a single class, as the mammalia for example. The correspondence of 

 anatomical structure argues a correspondence of function. And judg- 

 ing from the general analogy of part with part, we are led to expect a 

 similarity of function in each part compared with its analogue in the 

 brains of different animals. The cerebrum having been ascertained to 

 be the part whose reactions constitute the phenomena of intelligence, 

 we have that much reason to conclude that intelligence may be looked 

 for wherever there is a cerebrum. Allowance must be made, of course, 

 for the size of the cerebrum, and it cannot be expected that reactions 

 of as great number and variety can be obtained from a small as from a 

 large cerebrum, other things equal. But one intelligence is precisely 

 like another, as far as it goes. There is no difference between horse 

 sense and man sense, up to the limit of the horse's capacity. I knew a 

 horse once who knew enough to work a pump-handle up and down in 

 order to get a drink of water. He got but a little at a time, because as 

 soon as he saw a little water in the trough he stopped pumping and 

 drank what there was, then pumped some more, and so on, showing his 

 foresight to be qualitative, though not to a great extent quantitative. 

 It is true he did not know anything about the internal construction of 

 the pump, or why the water came when the handle went down. But he 



