206 FUNCTIONS OF THE NERVOUS SYSTEM. 



ceding section, to be not improbably the centres of the instincts and emotions 

 of higher animals. 



280. On comparing Birds with Insects, we at once see a very remarkable 

 difference in the character of their actions. Their instinctive tendencies are 

 of nearly the same kind; and the usual arts which they exhibit in the con- 

 struction of their habitations, in procuring their food, and in escaping from 

 danger, must be regarded as intuitive, on account of the uniformity with 

 which they are practised by different individuals of the same species, and the 

 perfection Vith which they are exercised on the very first occasion. But in 

 the adaptation of their operations to peculiar circumstances, Birds display a 

 variety and fertility of resource far surpassing that which is manifested by 

 Insects ; and it is not doubted, by those who have attentively observed their 

 habits, that in such adaptations they are often guided by real intelligence. 

 This must be the case, for example, when they make trial of several means, 

 and select that one which best answers the purpose ; or when they make an 

 obvious improvement from year to year in the comforts of their dwelling ; or 

 when they are influenced in the choice of a situation by peculiar circumstances, 

 which, in a state of nature, can scarcely be supposed to affect them. The 

 complete domesticability of many Birds is in itself a proof of their possessing 

 a certain degree of intelligence ; but this alone does not indicate the possession 

 of more than a very low amount of it ; since many of the most domesticable 

 animals are of the humblest intellectual capacity, and seem to become attached 

 to Ma*n, principally as the source on which they depend for the supply of 

 their animal wants. This is the case with most Herbivorous quadrupeds, and 

 with Rabbits, Guinea-pigs, &c., as well as with the Gallinaceous Birds. The 

 attachment of the Dog or the Elephant is evidently of a much higher kind, 

 and involves a much larger number of considerations ; and their actions are 

 evidently the result, in many instances, of a complex train of reasoning, differ- 

 ing in no essential respect from that which Man would perform in similar 

 circumstances. The epithet, " half-reasoning," commonly applied to these 

 animals, does not express the whole truth ; for their mental processes are of 

 the same kind with those of Man, and differ more in the degree of control 

 which the animal possesses over them, than they do in their own character. 

 We have no evidence that any of the lower animals have a voluntary power 

 of guiding, restraining, or accelerating their mental operations, at all similar to 

 that which Man possesses ; these seem to be of very much the same character 

 as those which we perform in our dreams, different trains of thought com- 

 mencing as they are suggested, and proceeding according to the usual laws, 

 until some other disturb them. Although it is customary to regard the Dog 

 and the Elephant as the most intelligent among the lower animals, it is not 

 certain that we do so with justice ; for it is very possible that we are misled 

 by that peculiar attachment to Man which in them must be termed an instinct, 

 and which enters as a motive into a large proportion of their actions ; and that, 

 if we were more acquainted with the psychical characters of the higher 

 Gluadrumana, we should find in them a greater degree of mental capability 

 than we now attribute to them. One thing is certain, that, the higher the 

 degree of intelligence which we find characteristic of a particular race, the 

 greater is the degree of variation which we meet with in the characters of 

 individuals ; thus every one knows that there are stupid Dogs and clever 

 Dogs, ill-tempered Dogs and good-tempered Dogs, as there are stupid Men 

 and clever Men, ill-tempered Men or good-tempered Men. But no one could 

 distinguish between a stupid Bee and a clever Bee, or between a good-tem- 

 pered Wasp and an ill-tempered Wasp, simply because all their actions are 

 prompted by an unvarying instinct. 



281. Before inquiring into the comparative size of the Cerebrum, in different 



