the lower jaw upon the upper may be likened to the beating of a hammer on an anvil. When the jaw muscles are powerful the lower jaw is brought with a considerable force against the upper jaw, and consequently the arches which connect the upper jaw with the cranium must be proportionately well developed. Conversely the weakening of the jaw muscles permits, for example, the outer rim of the orbit and the zygomatic arch to be of a more delicate construction.

The increase of the brain causes the forehead to be at the same time broader and higher. This fact was noted by the sculptors of ancient Greece, and they increased the vertical height of the forehead of some of their gods, so that, as in the case of Zeus, this human character was carried by them beyond. human limits, when they wished to emphasize the benevolence and mental superiority of the Father of gods and men.

When at an indoor gathering we see a number of men with their hats off we notice that their heads vary in form. Some are small, others large; some have long heads, others have short ones; the head may be high or low, and the contours vary in diverse ways. These differences render the study of craniology peculiarly difficult, as it is almost impossible to describe most of them at the same time succinctly and intelligibly, and also because innumerable com

binations of variable elements may occur in a collection of skulls from a single district.

Dr. D. G. Brinton, the well-known American anthropologist, has been so impressed with the latter fact, that he despairs of the study of craniology throwing any certain light on the racial problems of Anthropology. Undoubtedly an immense amount of tedious labour has been expended by enthusiastic students on the study and description of skulls, but often, one must confess, with very meagre results. There certainly is a wonderful fascination in skulls; and craniology, which to the outside observer appears to to be about as uninteresting a subject as could well be conceived, has lured its votaries to more and more persistent and painstaking effort. The present writer, who once sat in the seat of the scornful, has also yielded to the charming of craniology.

A very strong argument in favour of craniology is the assistance that it should render to prehistoric archæology and to the history of peoples. We have documentary and legendary records of the shifting of populations, and our archæological museums are full of interesting records of the past. It would be a matter of great importance if the skulls that are exhumed could also be brought in as evidence.

We are again face to face with the question that confronted us when considering the colour of the

F

eyes and hair. Can one particular head-form, or a restricted number of head-forms, be regarded as characteristic of a race or consanguineous group?

Upper and side views of a Kalmuk's and of a Negro's skull; after Ranke.

And are these characters sufficiently constant to be of scientific value?

Before we can attempt to answer these two questions, it will be necessary to give a brief

account of the methods and nomenclature of craniometry. Fortunately, a very short description will serve the present purpose, as we are concerned with only one or two aspects of the subject, and not with craniology as a whole.

On looking at a number of skulls from above, it is seen that they are all longer than broad, though some are less so than others, and that the contour is very varied. Some may have somewhat flat sides, others have gently rounded sides, or the skull may appear narrow in front and swollen behind; indeed, there may be great variation in this respect even in skulls which have the same relation of breadth to length. Skulls must also be looked at from the front, side, back, and underneath, and their peculiarities noted.

The character which is most frequently recorded is the ratio of the breadth of the skull to its length. One speaks loosely of a long or a narrow, or of a short or round skull, but such vague descriptions are of no scientific value. Anthropologists now adopt the plan of calculating indices which accurately express this numerical relation. The extreme length and breadth of a skull are measured, the breadth is multiplied by one hundred, and the total is divided by the length, the result is the cranial index.

In other words the length is reduced to one hundred, and the ratio of the breadth to that is the index.

The altitudinal index is the ratio of the height either to the length or to the breadth.

Directions for taking these measurements will be found in the chapter dealing with practical instructions. There are numerous facial measurements from which various indices are obtained, but these do not concern. us at present.

The cranial index is usually grouped into three series; a skull is said to be dolichocephalic when its index does not exceed 75, to be mesaticephalic between 75 and 80, and to be brachycephalic when over 80. Some investigators who aim at great exactness increase the range in the following manner :—

There is a tendency in some quarters to extend dolichocephaly up to 77'9, so as to reduce mesaticephaly to the narrow range of 78 to 80.