M. L. TiLDESLEY 
201 
or elevated the pointer .if necessary wlien approaching one of these characters, in 
order to pass right over or along it, and represent it properly in the tracing*. 
We now take the horizontal line through the nasion, i.e. the line linking the 
nasion to the gamma (y), as our horizontal axis, and divide it into ten equal pieces 
with the jjroportional compasses. The nasion counting as 0 and the other divisions 
from nasion to gamma as 1, 2, ... 9, ordinates above are drawn through these ten 
points perpendicular to the axis, also through a point (iVj) at a quarter of the 
distance of 1 from N, and two points {yl and y|) a quarter and an eighth of the 
distance of 9 from gamma respectively. Ordinates 8, 9 and yl are produced below 
the axis, to the contour line, and another ordinate is added below it from a point 
yf, halfway between 9 and y. Ordinates are drawn from the bregma, lambda, 
opisthion, and sub-orbital point perpendicular to the axis. Vertical tangents to 
the most projecting points of the glabellar and occipital regions are drawn to Ny 
produced, the points of contact being named G and Oc respectively. 
The basion is joined to the nasion and gamma; so also is the inion. The alveolar 
point is joined to the nasion and basion, giving the fundamental triangle. To 
determine the vertex a horizontal tangent is drawn to the top of the skull, and 
an ordinate drawn to Ny from the point of contact. To give some measure of nasal 
characteristics, the tip (L) of the nasal contour has been joined to the nasion, so 
that NL gives the nose length, and the angle between NL and Ny is the angle of 
nasal prominence. Some nasal ridges exhibit a double curve, turning downward 
towards the tip so that for a Uttle distance NL either cuts the outline or coincides 
with it. The point where NL first meets the outUne of the ridge is marked L', and 
NL' is also measured; where there is no double curve NL of course is equal to 
NL'. The maximum subtense is drawn from NL to the curve above L'. 
It was desired to take some measurement of the proportions of the palate. A 
horizontal was therefore drawn through the alveolar point and a vertical line drawn 
to it through the point where the left half of the transverse palatine suture meets the 
sagittal palatine suture. Another horizontal was drawn through the highest pointf 
in the cSntour taken along the palatine process of the maxilla, and the junction of 
this with the vertical already drawn gave the point P of which I have measured 
the co-ordinates. It will be seen that I have taken measurements only of the 
palatine process, the ordinate of P giving its greatest vertical height, and the 
abscissa its horizontal length. 
Finally, a line is drawn through the sub-orbital point parallel to the A'^y line, 
and a perpendicular dropped to this from the apex gives the auricular point which 
is to be used for the contours. Now if the plane passing through the nasion, bregma 
and lambda, which we have used as our sagittal plane, were exactly at right angles 
to the horizontal plane defined as passing through the left sub-orbital point and 
* Our Klaatsch tracer is provided with a vertical knife-edge as well as a tracing pointer to meet 
these difficulties, but as the pointer must be used for horizontal and transverse sections the labour of 
attachment of the knife-edge for the sagittal is against its use. Duplicate instruments would be desirable. 
■j- It very frequently occurs that the point where the sutures meet is itself the highest point. 
