Elements of phrenology / [George Combe].

  • George Combe
Date:
1850
Catalogue details

Licence: Public Domain Mark

Credit: Elements of phrenology / [George Combe]. Source: Wellcome Collection.

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    hand (the chief instruments of touch), are in man five times greater in volume and surface than those going to the muscles ; whereas, in the horse and other animals with imperfect touch and great muscular strength, the proportions are so much reversed, that the mass of the muscular nerves exceeds that of the sensitive nerves by one-third. Again, in the case of the other external senses, the size of the nerves is always proportioned, ceteris paribus, to the intensity of the function. Monro, Blumenbach, Cuvier, and Magendie, state this fact. In fishes, Desmoulins found the auditory nerve twenty times larger in proportion to the size of the animal than in mammalia and birds—water being less fit than air for the transmission of sound. Those animals which en- joy an acute sense of smell are remarkable for the great size of their olfactory nerves. For instance, the bear, the sheep, the dog, and the cow, have a large surface of the internal nostrils covered with nervous fibrils. In like manner, large nerves of taste uniformly attend supe- riority in that function, And in vision the same pro- portion between size of organ and intensity of function is most remarkably displayed. In eagles, whose sight is very keen, the ganglions whence the optic nerves arise are equal in size to one-third of the whole brain ; whereas in the owl, which sees imperfectly, they are not equal to more than one-twentieth. In birds of prey, the nervous expansion of the retina in the eye is said by Desmoulins to be curiously folded and doubled upon itself, for the purpose of affording room for a large surface in a small space, these folds disappearing when the birds are con- fined for a length of time to near vision, as in a cage; but the correctness of this observation has been denied. The brain forms no exception to the law which we are considering ; and most physiologists admit that the mental manifestations are vigorous in proportion to its size, all other things being equal. Cuvier and Magendie are no mean authorities. In speaking of the cerebral lobes being the place ‘where all the sensations take a
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