Page:Popular Science Monthly Volume 6.djvu/583

Rh in chronic renal inadequacy. There is usually decided hypertrophy of the left ventricle, and a high arterial tension, originating in a contracted condition of the terminal arteries. As a consequence of this tension, the blood-pressure on the brain is well sustained; and a free supply of arterial blood, rendered perhaps more than ordinarily stimulating by the presence of nitrogen in excess, evokes a heightened activity of the cerebral cells. Simple hypertrophy of the heart is mostly found in the subjects of chronic renal changes. That there is a certain explosiveness in the gouty, together with much mental activity, is simply a clinical fact. The excess of nitrogen in the blood stands in a suggestive relationship to the explosive irritability, while the high blood-pressure is evidently causally related to the heightened mental activity. The two factors requisite for rapid evolution and discharge of force by the cerebral cells are found together under the above-named combination. If the changes in the circulation are imperfect, and the blood-pressure is but low, or even normal, the gouty person is not mentally inactive, but is despondent.

Bichat observed that the length of the neck exercises an influence over the mental activity of the individual. Persons with short necks have a better sustained power of work than those who have long necks, or, in other words, other things being equal, the brain, which is superimposed on a short neck, has an advantage over the brain fed by a long carotid artery. Van der Kolk is in agreement with Bichat upon this point. An extensive series of observations inclines me to agree with them.

Van der Kolk also quotes from Haller the observation that rickety children have generally large heads, and possess quick perceptive faculties; and that the blood-vessels of their heads are distinguished for their large calibre. Certainly such children are commonly very precocious. There is a point, however, in relation to this matter which must not be overlooked. Rickety children are usually of scrofulous tendency, and in the scrofulous there is usually an excess of lithates in the blood, which will not be without the ordinary effect exercised by nitrogen on the brain. The great Dutchman also states, "It is a known fact that hunchbacked individuals, in whom the blood flows more quickly and strongly toward the brain, are remarkable for vivacity of spirit." It will not do, in this consideration, to leave out of the question the possibility of a mental factor; that the physical deformity turns the mind of the individual toward mental cultivation as a compensation for bodily defects. Granting this, we must also remember that mere will and perseverance exercise a limited influence, and only permit a brain to make the most of itself. What exists there potentially, it may draw out into actual manifestation; but with this the power of the will ceases. An effort of the will may and does dilate the blood-vessels of the brain, and permits larger circulation through it; but the general blood-pressure in the systematic vessels