That ordinary alimentation, which includes the process of digestion, the subsequent vital changes involved in the conversion of food into blood, and its final transformation into tissue, causes mental languor and dullness, as well as bodily exhaustion, is attested by universal experience. A torpid condition of the liver, one of the most inveterate of chronic derangements, is indicated by sullenness, melancholy, despondency, loss of interest in the affairs of life, sluggishness, etc., and the ultimate tendency of this morbid state is towards suicide. A broad and deep development of the middle lobe of the brain, shown by a fullness under the chin, and of the adjacent portion of the neck, denotes tendencies to somnambulism, delirium, and insanity. If such characteristics of the organization do not culminate in mental derangement, they exhibit childishness, helplessness, and great dependence. Age abates the vigor of the executive faculties, and old people manifest not only bodily infirmities, but the relaxing and enfeebling influences proceeding from the lower portions of the brain. They totter about in their second childhood, mentally and physically enervated. Those who become dissipated by the use of intoxicating beverages are not only weak, trifling, and foolish, but walk with an unsteadiness which betrays their condition. These illustrations show that this part of the brain is destitute of energy. Diseases of the digestive organs also indicate it. Cholera, whether induced by invisible animalcules in the air, or in water, takes the route of the alimentary canal, opens the vital gates, and myriads of victims are swept down to death. It proves remarkably fatal to those having this cerebral conformation. Perhaps enough has been said to indicate the relaxing and enfeebling tendencies of this region of the brain. They may be classified as follows:
| { | SERVILITY, | |
| CAUTIOUSNESS, | ||
| FEAR, | ||
| Cerebral Functions: | ANXIETY, | |
| SENSIBILITY, | ||
| CUNNING, | ||
| PROFLIGACY. | ||
| { | ATONIC, | |
| Physiological conditions | EXCITABILITY, | |
| and tendencies: | RELAXATION, | |
| FEEBLENESS, | ||
| DISEASE. |
This classification shows their tendencies to chronic disease, functional derangement, insanity, and suicide.
GENERAL CONSIDERATIONS.
Before the structure of the brain was understood, Buffon spoke of it as a "mucous substance of no great importance." Its functional significance was so slightly appreciated that some people hardly suspected they had any brains, until an accident revealed their existence. Latterly, however, it is generally understood that the perfection of an animal depends upon the number and the development of the organs controlled by the nervous system, the sovereign power of which is symbolized by a grand cerebrum, the throne of Reason. That animal which is so low in the scale of organization as to resemble a vegetable, belongs to an ascending series ending in man. The lowest species have no conscious perception, and their movements do not necessarily indicate sensation or volition. Instinct culminates in the Articulates, especially in Insects; while created intelligence reaches its acme in man, the highest representative of the Vertebrates.
"All things by regular degrees arise—
From mere existence unto life, from life
To intellectual power; and each degree
Has its peculiar necessary stamp,
Cognizable in forms distinct and lines."—LAVATER.
Man, in the faculties of mind, possesses more than a complement for instinct; some of the lower animals, however, seem to share his rational nature, and to a certain degree become responsible to him. Finally, the manifestations of mind bear a relation to the development of cerebral substance, and to the bodily organization which supplies the brain with blood. Fig. 76 shows the relative amount of brain matter in the lower animals, compared with that of man; the peculiarities of each agreeing with its cerebral conformation. It is easier to measure the capacity of skulls in different races than to procure and weigh their brains. The following table has been published.
| Race. | CUBIC INCHES. |
|---|---|
| Swedes, | 100.00 |
| Anglo-Saxons, | 96.60 |
| Finns, | 95.00 |
| Anglo-Americans, | 94.30 |
| Esquimaux, | 86.32 |
| North America Indians, | 84.00 |
| Native Africans, | 83.70 |
| Mexicans, | 81.70 |
| American Negros, | 80.80 |
| Peruvians and Hottentots, | 75.30 |
| Australians, | 75.00 |
| Gorilla, adult, | 34.50 |
| Idiot, | 22.57 |