THE NERVOUS SYSTEM. 97 



It was at one time thought that the brain of man was not only 

 relatively, but absolutely, larger than that of any other animal ; 

 but it is now known that the amount of nervous matter in the 

 elephant's brain, and in some others, is greater. Relatively, how- 

 ever, to the size of their bodies, the comparison is more in our 

 favor. For example : in man, the ratio of the weight of the brain 

 to that of the whole body is about one to 28, while in the dog it 

 averages about 1 to 160, in the horse 1 to 400, and in the elephant 

 1 to 500. But again, on the other hand, it is curious to remark, 

 that the brain of the canary bird, compared with its body, is as high 

 as 1 to 14 ; and there is a species of monkey in which the propor- 

 tion is even 1 to 11. For various reasons, however, comparisons of 

 this kind are not considered as furnishing a fair estimate. Another 

 method has been proposed by Soemmering, an eminent physio- 

 logist, to which hitherto few if any exceptions have been found, 

 and which depends on the ratio which the size of the brain holds to 

 the aggregate bulk of the nerves that proceed from it. As an illus- 

 tration of this method, the example of the horse may be cited. 

 The absolute size of the Brain of the horse is only about half that 

 of the human brain, while the mass of the nerves of the horse, at 

 their origin, is no less than ten times greater than that of man. 



By adopting this principle, we are able, in most instances at least, 

 to trace a correspondence between the cerebral development and 

 the amount of intelligence, and we pass by easy gradations, from 

 one class of animals to another upwards to man, between whom and 

 all the rest there exists a great gap. Between the two extremes 

 the difference is very striking. To show this, we weighed a cod, 

 and found it to be 27 pounds. We weighed its brain (including all 

 the nervous matter above the medulla oblongata), and found it to 

 be 44 grains. As a comparison we weighed a child, which died 

 four days after birth, and found it to be seven pounds. Its brain 

 was also weighed, and was found to be no less than 6912 grains. 

 A similar comparison may be made with the adult brain. Mr. 

 Scoresby found the brain of a young whale (whose body weighed 

 11,200 pounds) to be 3 pounds 12 ounces. The body of Byron or 

 Cuvier would probably not weigh more than 200 pounds, and yet 

 the brain of the former is said to have weighed 4J pounds, while 

 Cuvier's brain weighed 4 pounds 13J ounces* the heaviest we 

 believe upon record. 



From the great mass of nervous matter which man's brain con- 



* Brigham on the Influence of Mental Cultivation on the Brain. 



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