prey, have large ears directed backwards, their eyes warning them of danger before."

These observations apply to the external portion of the organs of sense. The inner parts or nerves are likewise subject to the same law of size. Georget, a late physiological writer, in treating of the nerves, says, "The volume of these organs bears a uniform relation, in all the different animals, to the extent and force of the sensations and movements over which they preside. Thus, the nerve of smell in the dog is larger than the five nerves of the external senses in man." The nerve of smell is small in man and in the monkey tribe; scarcely, if at all, perceptible in the dolphin; large in the dog and the horse, and altogether enormous in the whale and the skate, in which it actually exceeds in diameter the spinal marrow itself. In the mole it is of extraordinary size, while the optic nerve is very small. In the eagle the reverse is observed, the optic nerve being very large, and the olfactory small. Most of the quadrupeds excel man in the acuteness of their hearing, and accordingly it is a fact that the auditory nerve in the sheep, the cow, the horse, &c., greatly exceeds the size of the same nerve in man. In some birds of prey, which are known to possess great sensibility of taste, the palate is found to be very copiously supplied with nervous filaments.

But the organ of sight affords a most interesting example of the influence of size. The office of the eye-ball is to collect the rays of light. A large eye, therefore, will take in more rays of light, or, in other words, command a greater sphere of vision, than a small one. But to give intensity or power to vision, the optic nerve is also necessary. Now, the ox placed upon the surface of the earth is of a heavy structure and ill fitted for motion, but he has a large eye-ball which enables him to take in a large field of vision without turning; but as he does not require very keen vision to see his provender on which he almost treads, the optic nerve is not large in proportion to the eyeball. The eagle, on the other hand, by ascending to a great height in the air, enjoys a wide field of vision from its mere physical position. It looks down from a point over an extensive surface. It has no need, therefore, of a

large eyeball to increase artificially its field of vision; and, accordingly, the ball of its eye is comparatively small; But it requires, from that height, to discern its prey upon the surface of the earth, and not only is the distance great, but its prey often resembles in color the ground on which it rests. Great intensity of vision, therefore, is necessary to its existence. Accordingly, in it the optic nerve is increased to an enormous extent. Instead of forming a single membrane lining only the inner surface of the posterior chamber of the eye, as in man and animals of ordinary vision, and consequently only equalling in extent the sphere of the eye to which it belongs, the retina or nerve of vision in these quick-sighted birds of prey is found to be composed of a great number of folds, each hanging loose into the eye, and augmenting, in an extraordinary degree, not only the extent of nervous surface, but the mass of nervous matter, and giving rise to that intensity of vision which distinguishes the eagle, falcon, hawk, and similar animals. In the case of all the senses, then, the law holds, that power of function is in proportion to size of the organ, other circumstances being equal.

Let us now attend to the brain. Were I to affirm that difference of size in the brain would produce no effect on the vigor of its functions, or that a small brain in perfect health, and of a sound constitution, is equal in functional power and efficiency to a large one in similar condition, Would the reader, after the evidence which has been laid before him of the influence of size in increasing the power of function in all other parts of the body, be disposed to credit the assertion? He would have the utmost difficulty in believing it, and would say that if such were the fact, the brain must form an exception to a law which appears general over organized nature; and yet the phrenologists have been assailed with every species of vituperation, for maintaining that the brain does not form an exception to this general law, but that in it also vigor of function is in proportion to size, other conditions being equal. I shall proceed to show some evidence in proof of this fact; but the reader is requested to observe that I am here expounding only general principles in an introductory discourse. The conditions

and modifications under which these principles fall to be applied in practice, will be stated in a subsequent chapter.

First, The brain of a child is small, and its mental vigor weak, compared with the brain and mental vigor of an adult.* Secondly, Small size in the brain is an invariable cause of idiocy. Phrenologists have in vain called upon their opponents to produce a single instance of the mind being manifested vigorously by a very small brain. Deficiency of size, however, in the brain is not the only cause of idiocy. A brain may be large and diseased, and mental imbecility arise from the disease; but, although disease be absent, if the size be very deficient, idiocy will be invariable. Thirdly, Men who have been remarkable, not for mere cleverness, but for great force of character, such as Napoleon Bonaparte, have had large heads. Fourthly, It is an ascertained fact, that nations in whom the brain is large, possess so great a mental superiority over those in whom that organ is small, that they conquer and oppress them at pleasure. The Hindoo brain, for example, is considerably smaller than the European, and it is well known that a few thousands of Europeans have subdued and keep in subjection millions of Hindoos. The Native American brain is smaller also than the European, and the same result has been exemplified in that country. Lastly, The influence of size is now admitted by the most eminent physiologists. Magendie says, "the volume of the brain is generally in direct proportion to the capacity of the mind. We ought not to suppose, however, that every man having a large head is necessarily a person of superior intelligence, for there are many cases of an augmentation of the volume of the head beside the size of the brain, but it is rarely found that a man distinguished by his mental faculties has not a large head. The only way of estimating the volume of the brain, in a living person,

*

It is certified by practical hatters, that the lower classes of the community, who are distinguished for muscular vigor much more than mental capacity, require a smaller size of hat than those classes whose occupations are chiefly men tal, and in whom vigor of mind surpasses that of body. But the Phrenologist does not compare mental power in general with size of brain in general; and, besides, the hat does not indicate the size of the whole head. The reader will find details on this point in the 4th volume of the Phrenological Journal.

measure the dimensions of the skull; every other means, even that proposed by Camper, is uncertain."-(Compendium of Physiology, p. 104. edition 1826). The following passage which occurs in the 94th Number of the Edinburgh Review, also implies not only that different parts of the nervous system, including the brain, have different functions, but that an increase of volume in the brain is marked by some addition to, or amplification of, the powers of the animal. "It is in the nervous system alone that we can trace a gradual progress in the provision for the subordination of one (animal) to another, and of all to man; and are enabled to associate every faculty which gives superiority with some addition to the nervous mass, even from the smallest indications of sensation and will, up to the highest degree of sensibility, judgment, and expression. The brain is observed progressively to be improved in its structure, and, with reference to the spinal marrow and nerves, augmented in volume more and more, until we reach the human brain, each addition being marked by some addition to, or amplification of, the powers of the animal,-until in man we behold it possessing some parts of which animals are destitute, and wanting none which theirs possess. There is here, then, pretty strong evidence and authority for the assertion, that the brain does not form an exception to the general law of organized nature, that other conditions being equal, size of organ is a measure of power of function.

The circumstances which modify the effects of size fall next to be considered. These are constitution and health.

The question naturally presents itself, Do we possess any index to constitutional qualities of brain? The temperaments indicate them to a certain extent. There are four temperaments, accompanied with different degrees of activity in the brain-the Lymphatic, the Sanguine, the Bilious, and the Nervous. The temperaments are supposed to depend upon the constitution of particular systems of the body; the brain and nerves being predominantly active from constitutional causes, produce the nervous tempera

ment; the lungs, heart, and blood-vessels being constitutionally predominant, give rise to the sanguine; the muscular and fibrous systems, to the bilious; and the glands and assimilating organs, to the lymphatic.

The different temperaments are indicated by external signs, which are open to observation. The first, or Lymphatic, is distinguishable by a round form of the body, softness of the muscular system, repletion of the cellular tissue, fair hair, and a pale clear skin. It is accompanied by languid vital actions, with weakness, and slowness in the circulation. The brain, as part of the system, is also slow, languid, and feeble in its action, and the mental manifestations are proportionally weak.

The second, or sanguine constitution, is indicated by well defined forms, moderate plumpness of person, tolerable firmness of flesh, light hair, inclining to chestnut, blue eyes, and fair complexion, with ruddiness of countenance. It is marked by great activity of the blood-vessels, fondness for exercise, and an animated countenance. The brain partakes of the general state, and is active.

The Bilious temperament is recognised by black hair, dark skin, moderate fulness, and much firmness of flesh, with harshly expressed outline of the person. The functions partake of great energy of action, which extends to the brain, and the countenance, in consequence, shows strong, marked, and decided fea

tures.

The Nervous temperament is recognised by fine thin hair, thin skin, small thin muscles, quickness in muscular motion, paleness of countenance, and often delicate health. The whole nervous

system, including the brain, is predominantly active, and the mental manifestations are proportionally vivacious.*

It it thus clearly admitted, that constitution or quality of brain

The American reader will find a very elegant and instructive account of the temperaments, by that distinguished Phrenologist Dr. Charles Caldwell, of Lexington, in a volume published there in 1831, under the title of "Essays on Malaria and Temperament."