J. F. Tocher 
195 
show that regions of excess of medium hair are not regions of excess but of defect 
of dark and jet black hair. This would seem to indicate a greater approach 
towards fusion of the fair and dark types in more densely populated centres and 
the consequent gradual disappearance of these types to form the medium (brown 
or dark brown) type. There is no bias for or against the presence of red as 
a class with excess of medium hair. Excess of red hair is found as a rule only in 
regions where the proportion of the dark-haired class is well below the average. A 
slight excess of fair is associated with excess of red. The probable reasons for 
these positive and negative associations will not be further entered into here. 
Sufficient evidence has not yet been accumulated to explain the differences with 
regard to pigment and matrix in human hair*. The present grouping of the shades 
into five classes is based on the general appearance of hair in the mass. The 
problem generally is one on inheritance, but the material to solve the problem 
comes from divers sources, chemical, microscopical, biological, statistical. Until 
this material is collected and dealt with, no explanation of any great weight from 
a scientific point of view can be given, particularly as to the shades of red 
hair, although several quite plausible theories can quite easily be advanced. One 
must therefore be content to state the bare facts as they emerge from the statis- 
tical analysis. It does not appear to be an insoluble although perhaps it is a 
somewhat difficult problem. When more light is obtained the explanation will be 
forthcoming. 
(/3) Eye classes associated with one another. — Excess of dark eyes in densely 
populated centres. The only class which is not positively associated significantly 
with any other class is the class of light eyes. Excess of light is negatively 
associated with blue and dark. Where light eyes are in excess, blue and dark eyes 
are not likely to be so, but the reverse ; there is likely to be a defect of these 
classes. Excess or defect of light eyes is not connected with any excess or defect 
of medium eyes. Excess of blue eyes is as a rule associated with defects in the 
frequencies of the other classes of eye colour. Excess of dark eyes accompanies 
excess of medium and defect of the other two, light and blue. So that, broadly 
speaking, it is found that excess of blue eyes is found alone, excess of light eyes is 
found alone and excesses of dark eyes and medium eyes occur together. This is 
an interesting result, since it has been shown by both Galton and Pearson that 
exclusive inheritance prevails in the dark-eyed class. That is to say, the offspring 
for example of parents one dark-eyed and the other light-eyed or blue-eyed are, 
as a rule, either dark-eyed or light-eyed or blue-eyed. Medium eyes do not 
usually appear from such unions. There is no evidence as yet as to the blending 
or otherwise of the three classes, blue, light and medium. But since the offspring 
of parents, one dark-eyed and the other medium eyed, are likely to be either dark- 
eyed or medium eyed, unions among the two classes for generations would have no 
appreciable effect on the eye colour of the offspring, and therefore, as the results of 
* The chemical and microscopical aspects of the problem of hair colour will be dealt with by the 
author iu another memoir. 
