A little anatomical knowledge will prevent us from being deceived, and enable us to make due allowances. There are no great difficulties in making a correct estimate, and the anatomists who have taught their pupils that correct cranial observations could not be made, only showed their own ignorance of the subject. We must consider the cranium as though all osseous protuberances had been shaved off, leaving the smooth, curving contour of the skull. The principal projection to be removed is the superciliary ridge corresponding to the brow at the base of the forehead. It is formed by the projection of the external plate of the skull, leaving a separation or cavity between it and the inner plate, which cavity is called the frontal sinus, and is sometimes half an inch wide. As there is no positive method of determining its dimensions in the living head, there must ever be some doubt concerning the development of the perceptive organs which it covers. The superciliary ridge at the external angle of the brow extends really as much as three-quarters of an inch from the brain. From this angle a ridge of bone (the temporal arch) extends upward and backward, separating the lateral surface of the head from the frontal and upper surfaces. This ridge is a convenient landmark, but must be excluded from an estimate of development as it is merely osseous. It extends back on the head a little behind its middle. The sagittal suture on the median line of the upper surface usually presents a slight, bony elevation or ridge (see the engraving of the skull, Chapter III.), and the lambdoid suture on the back of the head is frequently rough. A superficial practical phrenologist (of great pretensions) at Cincinnati, in examining the head of a gentleman of mild character, found the lambdoid suture quite rough, and gave him a terrifically pugnacious character, not knowing enough to distinguish between osseous and cerebral development. The occipital knob on the median line between the cerebrum and cerebellum, has been already mentioned. The mastoid process, the bony prominence behind the ear is a projection exterior to the cerebellum. Where it starts from the cranium above and behind the cavity of the ear, we may judge of basilar development by the breadth of the head, but the basilar depth which is more important is to be judged by the extension downward, which was illustrated in the last chapter by comparing the skulls of J. R. Smith and the slave-trading count.
To judge the comparative strength of the higher and lower elements of character, we look for the height above the forehead and the depth at and behind the ear, which is ascertained by placing the hand on the base of the cranium behind the ears, while the height of the head is best appreciated by placing a hand on the top with the fingers reaching down to the brow.
In a profile view the human head may be divided into three equal parts, the length of the nose being the central part, from the nose to the end of the chin another, and the remainder above the nose the third part. In inferior heads these three measurements are equal, the upper third extending to the top of the head; but in heads of superior character the upper third extends only to the top of the forehead, and the outline of the head rises a half breadth above the forehead, as the following profiles show. In heads of the lowest character the basilar depth exceeds the height, as in the French Count and the Indian Lewis.
The contour of a well-developed head forms a semicircle above the base line through the brow, and its elevation above that line is equal to one half of the antero-posterior length of the head, while in the inferior class of heads the elevation is but four-tenths of the length or even less, and is hardly equal to the depth, while in the highest class the elevation is one-half greater than the depth or even more. We obtain another view of the comparative height and depth by drawing lines from the brow to the vertex and the base of the brain and comparing the two angles thus formed. In the good head we observe the great superiority of the upper angle over that formed by the line to the ear, the lower end of which corresponds to the lowest part of the brain, the base of the cerebellum.
To take an illustration from nature, I would present the outlines of two Indian crania that I obtained in Florida,—Vacca Pechassee, or the cow chief, who headed a small tribe, and bore a good character among the whites, and Lewis, an Indian of bad character in the same neighborhood (on the Appalachicola River), who was shot for his crimes. (I might have obtained many more, but as the Seminole war was not then over, I found that my own cranium was placed in considerable danger by my explorations.)
In Vacca Pechassee the height is to the depth as 11 to 9; in Lewis as 9 to 11. In J. R. Smith the height is to the depth as 12 to 10; in the slave trading count as 9 to 14. This is the correct method of cranial study, for comparing the moral and animal nature.
The basilar depth was entirely overlooked in the old method of phrenologists, and hence they were very often mistaken in judging the basilar energy by breadth alone, of which there has been no more striking example than that of the Thugs of India, whose heads (though a tribe of murderers) were below the European average in basilar breadth. These facts are so conspicuous to any careful observer that I became very familiar with them in the first six months of my study of heads fifty-two years ago.
When the circulation of the brain is vigorous and regular, all portions being in regular activity, the fulness of the circulation being shown in the face, we may be sure that the character is fairly indicated by the cranium. The younger the individual the thinner the cranium, and the less the liability to deception by the thickness of the bones. Female skulls are generally more delicate than male, and also more normal or uniform in their circulation. Hence there is less difficulty in making an accurate estimate of women and of youth. The greater difficulty is found in men of thick skulls and abnormal brains, and these difficulties are in some cases insurmountable by mere measurement. It will become necessary in the depraved classes to look at the condition of the circulation about the head, and the facial indications of the organs that have been cultivated. If these are not sufficient to guide us we must fall back upon psychometry.