MIND AND THE NERVOUS SYSTEM. 15 



an intellect which is described as infantine. She could say a few 

 words, such as "good," "child," " morning," with tolerable distinct- 

 ness, but without connection or clear meaning, and was quite incapa- 

 ble of anything like conversation. Her habits were decent and cleanly, 

 but she could not feed herself — at least with any degree of method or 

 precision. She was fond of carrying and nursing a doll. In a case 

 described in a subsequent number of the same journal, by Professor 

 Marshall, the weight of the entire brain was but 8^ ounces. The sub- 

 ject was a boy twelve years of age. Nothing is said relative to the 

 intelligence manifested. 



Absohiteli/, the normal human brain is larger than that of any 

 other animal, except that of the elephant and the whale. Relatively to 

 the loeight of the body, it very greatly exceeds the proportion existing 

 in either. Leuret found the mean proportional weight of the brain to 

 the rest of the body to be in fishes as 1 to 5,668. The range in these 

 animals is, however, very great. In the bass, I found it, as the result 

 of eleven observations, to be as 1 to 523 ; in the eel, twenty-two ob- 

 servations, as 1 to 1,429 ; and in the gar-fish, nine observations, as 1 

 to 8,915. 



In reptiles of different orders Leuret determined the average to be 

 as 1 to 1,321. I found the proportion in frogs to be as 1 to 520 ; in 

 lizards, as 1 to 180 ; and, in the rattlesnake, as 1 to 1,825. The brain 

 of an alligator, over six feet in length, which I examined, weighed but 

 a little over half an ounce. 



Next in order come the birds, and here we find a very decided in- 

 crease in the proportion. From many determinations made by Haller, 

 Cuvier, Cams, and himself, Leuret gives the average as 1 to 212. In 

 the tomtit he found it as 1 to 12 ; in the canary-bird, as 1 to 14 ; in 

 the pigeon, as 1 to 91 ; in the duck, as 1 to 241 ; in the chicken, as 1 

 to 377 ; and, in the goose, as 1 to 3,600. These are very great differ- 

 ences, and, as Leuret remarks, have no constant relation to the intel- 

 ligence. It is worthy of notice that the brain is proportionally smaller 

 in those birds which are domesticated, and which, consequently, do 

 not have to make so severe a struggle for existence, than in the wild 

 birds ; and their brains, therefore, are more encumbered by fat. From 

 determinations that I made, it was ascertained that the brain of the 

 canary-bird reared in the United States was in weight compared to 

 that of the body as 1 to 10*5, and in the Arctic sparrow as 1 to 11. 

 No observations on record show proportionally larger brains than 

 these. 



Among mammals we find a still greater increase in the weight of 

 the brain as compared with that of the body. Leuret found it to 

 range in the monkeys from as 1 to 22, 24, and 25 ; in the dolphin it 

 was as 1 to 36 ; in the cat, as 1 to 94 ; in the rat, as 1 to 130 ; in the 

 fox, as 1 to 205 ; in the dog, as 1 to 305 ; in the sheep, as 1 to 351 ; 

 in the horse, as 1 to 700 ; and, in the ox, as 1 to 750. The mean for 



