D. Macdonald 
39 
[Editorial Note. Owing to the absence of Dr Macdonald from England it has 
not been possible to consult him as to several points in his most interesting paper. 
We think it might have been desirable to lay further stress on the possibility of 
considerable personal equation in the estimation of the " medium " class in both 
hair and eye colour. That 34 °/ o of the general population only should be of 
medium eye colour but 62°/ 0 of the scarlet fever population seems a very startling 
difference to attribute wholly to pigmentation. It does not accord with data 
reduced in the Biometric Laboratory and shortly to be published bearing on this 
point. In that material there was only one determination of the pigmentation of 
the general and the fever populations. It seems possible therefore that some of 
the above difference is due to personal equation which has led to the emphasising 
of the medium hair and eye colours in the fever population. Should this view 
be confirmed later, it would affect Dr Macdonald's conclusions (1), (2), (7) and 
(8), but not the important results (3), (4), (5) and (G), which depend upon 
estimates made solely in the fever hospital. There is some differentiation in 
age between Tocher's and Macdonald's populations. This is shown in the following 
table : 
Mean Ages. 
Hair ... 
Fair 
Bed 
Medium 
Dark 
Jet 
Black 
Totals 
Tocher 
Fever Cases, Boys 
„ „ Girls 
8-5 
8-7 
9-9 
8-8 
9-1 
9-5 
10-2 
10-3 
12-2 
10-5 
9-5 
9-4 
10-1 
10-2 
Eyes 
Blue 
Light 
Medium 
Dark 
Totals 
Tocher 
Fever Cases, Boys 
„ „ Girls 
7- 6 
8- 7 
9-0 
8-6 
9-7 
9-5 
10-0 
9-8 
9-6 
9-4 
10-1 
10-2 
It will thus be seen that the lighter haired children are younger than the darker 
haired, and that this is also substantially the case for the eye colour, the lighter 
being younger than the darker eyed. The fever population is 5 to 10 months 
younger than the general school population of Glasgow and we should accordingly 
expect it to be somewhat less dark than the latter. We should expect, as the fair 
pass with age into the medium class, that there would be a less percentage of 
medium in the fever than in the general population. Thus if there has been 
no personal equation, the conclusions (1), (2), (7) and (8) must be still further 
emphasised. K. P.] 
