HUMAN PHYSIOGNOMY. 13 measure acquired or modified from external circumstances, and the mode of life. Hence its general uniformity in nations and those pursuing similar avocations. Hence the nervous Italian, the phlegmatic Dutchman, the spare muscular soldier, the lymphatic gibbosity of “ mine host,” and the rubicund country squire, “ With wine and good fat capon lined.” We have next to consider the mode in which temperament influences mental action; and here a knowledge of physiology greatly avails us. No doubt exists as to the brain being the organ of mind. Whether the collection of phenomena we call “ mind,” is merely the proper function of the brain, or whether there is a spiritual essence inhabiting our earthly structure, which acts through the brain, are speculations equally useless and impossible of demonstration with those concerning the nature of light or the being of electricity. But, whichever hypothesis be the correct one, it is quite certain that the kind and degree of mental manifestations depend on the size and quality, and the consequent activity of the brain. There does not appear to be any further connection between temperament and the size of the brain than the general rule that it is comparatively small in the muscular and large in the nervous temperament. But the quality and activity of the brain are very much modified by the temperament. For the brain is an organ, possessing a similar texture, and subject to the same general laws, as the rest of the body ; hence like the muscles and other parts, its fibres are denser and more rigid, and consequently possess most intensity of action, in the Ner- ous temperament;—they are less so, aud it is supplied with more abundant and larger blood-vessels, in the Sanguine tern perament; whence, as we shall presently explain, its excitability ;—while in the Phlegmatic temperament, there is a greater quantity of watery lymph in its interstices, it partakes of the general flaccidity of the system, and is thereby rendered dull, inert, aud difficultly roused to feeble action. Numerous phenomena prove that the blood is the chief stimulus to the brain ; aud that in proportion to the rapidity with which it circulates through that organ, is mental action accelerated. Thus, when the brain ceases to receive its due supply .of blood, fainting, with a partial or entire abolition of mental power, supervenes; and the total insensibility and stupor of apoplexy results from a stagnation of the blood in the brain. Whereas the intense mental action in fever, frequently amounting to delirium, is chiefly due to the increased rapidity with which the blood circulates through the bruin; and the excitement of mind produced by wino owns a similar cause.
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