198 Pigmentation Survey of School Children in Scotland 
These results show that the distribution of cases of mental affection differs from 
those of the three other classes of defects. Excesses in the number of cases of 
imbecility, blindness and deafness occur in regions of excess of blue eyes and dark 
and jet black hair. From the results of the enquiry into the relationship between 
the Gaelic speaking portion of the population and pigmentation, it was shown that 
these were the classes correlated positively with excess of Gaelic speaking people. 
The correlation between this portion of the population and the four groups were 
accordingly calculated when it was found to confirm the conclusion that the Gaelic 
portion was correlated positively to those groups as expected, as the following table 
(Table XLIII.) shows : 
TABLE XLIII. 
Relationship between the Gaelic speaking Population 
and Defects. 
Defect or Affection 
Value of )• 
r 
-E(r=o) 
Deaf 
■865 
3^39 
Blind 
•884 
3-47 
Imbeciles 
•788 
3^09 
Deaf and Dumb . . . 
•295 
1-16 
From whatever cause, therefore,a significantly greater number of cases of imbecility, 
blindness and deafness occur in Gaelic speaking regions than occur throughout the 
country in general. Emigration of the fitter portion of the inhabitants from the 
west in greater proportion than from other parts of Scotland would explain the 
occurrence of larger proportions of cases of defect in the Highlands. It must not 
be concluded therefore that Gaelic speaking Scots on an average are in any way 
inferior physically to Lowland Scots — perhaps the reverse is the case — or that a 
really higher proportion of defects exist among the race or races which speak the 
Gaelic language. 
(10) Degree of resemblance between the Boy and Girl Populations in each of the 
Colour Classes. 
It has been seen in a general way that the boy and girl populations agree in 
many localities in showing excess or defect frequencies in the various classes 
compared with the general population, and in several cases it was found that the 
populations differed, excesses in one sex being associated with defects in the other 
and vice versa. It is necessary therefore that the difference between the two 
populations generally should be measured. It will be seen then which of the 
classes shows the greatest agreement and which the greatest difference, or whether 
there is any appreciable difference in the extent of association or independence of 
the two sexes as separate populations. 
(a) The degree of resemblance between the boy and girl populations in the 
same localities was determined, using in the first instance the percentage figures as 
