J. F. Tocher 
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frequently in contiguous areas, thus indicating a differentiation for each class 
from the general population. In measuring the degree of geographical separation 
or local segregation for each class, it has been proved that the blue-eyed and 
fair-haired classes have the greatest degree of local segregation. The segregation 
of these classes from the others is excessively great. Children belonging to these 
classes are congregated more in sparsely populated regions than in densely 
populated or moderately populated parts. The medium haired and medium eyed 
classes show the next greatest degree of local segregation. Children of these 
classes are congregated moi-e in towns and in densely populated parts. The 
other classes all show a high degree of segregation except the red-haired class, 
which is almost uniformly distributed throughout the country. But for the 
regions of excess in the north-east of Scotland and in one or two other isolated 
and much smaller areas the distribution of this class would be practically uniform. 
This fact suggests that the occurrence of red hair (a) is independent of race, 
or (/S) is one of the effects of blending of races, perhaps widely divergent races, 
or (7) is an abnormal condition in hair colour and deserves the attention of the 
physiologist and pathologist. The statement of Tacitus as to the red-haired 
Caledonians points at least to the fact that red hair was a trait among the 
inhabitants of the north of Scotland in earlier times, and it is a striking circum- 
stance that excess of this class is found in the region referred to by him. 
V. It has been found that regions of excess of the dark-haired, jet black 
haired and blue-eyed classes are associated with regions of excess of the Gaelic 
speaking population. The measure of the association is given. This association 
was to be expected, seeing that these classes occur in excess in western counties, 
where the population is bilingual and where Gaelic is the mother tongue of a 
large proportion of the inhabitants. A typical Scoto-Kelt is therefore blue-eyed 
and dark-haired, but the light-eyed dark-haired type is also common in Argyll 
and its Isles. It will be seen later (XVI.) that there is a similar Irish type. 
VI. It is proved that foreign immigrants tend to reside in the most densely 
populated areas in Scotland and in districts where families live in one or two 
rooms. The children of foreign immigrants have an effect, — scarcely an appre- 
ciable one, — on the population of Scotland as a whole, but in certain very densely 
populated parts they have a distinct effect. For example, it is shown that in 
certain divisions of Glasgow, Tradeston and Gorbals (see XVI.), the proportion 
of school children of foreign origin is so high as to change completely the nature 
of the distribution of hair colour and eye colour. 
VII. It is proved that densely populated regions are positively correlated with 
excesses of the following classes : medium hair, medium eyes and dark eyes. 
The more densely populated a region is the greater will be the proportions of 
these classes in the population, and conversely, the more sparsely populated a 
region is, the smaller on an average will be the proportion of the classes just 
named. 
