22 
point in the middle of the brow between the eyebrows, the 
glabella , Plate II, a , to the most prominent point of the 
occiput or back of head. It is the maximum length of the 
head. 
2. Transverse Breadth .—The maximum breadth of the 
head wherever it may be (except low down behind the 
ears) measured transversely to the length. The points of 
the instrument must be held exactly on the same level, both 
in relation to the vertical and the horizontal planes, other¬ 
wise the measurement will not be truly transverse. 
The cephalic index which indicates the relation the breadth 
of the head bears to the length is obtained by multiplying the 
breadth by ioo and dividing the product by the length, the 
formula being ^ x 1QQ = cephalic index. 
& Max. length r 
3. Length of Nose .—In making this measurement the 
instrument is held vertically, its lower point is placed lightly 
against the farthest back point of the under surface of 
the septum between the nostrils, Plate II, c , where the upper 
lip begins, not on the tip of the nose, the upper point at the 
termination or root of the nose between the eyes, b. This last 
point is sometimes a little difficult to determine. There is a 
small transverse fold of the skin (sometimes two folds) at the 
root of the nose ; it is on this fold, or when there are two 
folds, between the folds, that the upper point of the instru¬ 
ment should rest, generally about two millimetres above the 
level of the transverse axes of the eyes. 
4. Breadth of Nose .—Measured across the widest part 
without compressing the nostrils between the points of the 
instrument. 
These two measurements give the nasal index, the 
formula of which is = nasal index. 
The next four measurements show the distance of their 
several levels vertically below the plane of the top of the 
head. For directions as to how the instrument is to be 
used in determining them, see Instruments, p. 9. The 
position in which the head is held by the subject while these 
