A special test was carried out in Oxford by Mr. H.B.  English, who compared the capacity of boys in a school attended by children of the intellectual classes with that of boys in a very good primary school, whose fathers were shop-keepers, skilled artisans, etc., coming from homes which were good, with no sort of privation.  The result showed marked superiority of the sons of intellectual parents.  Mr. English concludes that the children of the professional classes, between 12 and 14 years of age, exhibit very marked intelligence, and he is convinced that the hereditary factor plays an altogether predominant part.

In another experiment, Miss Arlitt, of Bryn Mawr College, tested 342 children from primary schools in one district, who were divided into four groups:—­

     Group 1.  Professional. 
     Group 2.  Semi-professional and higher business. 
     Group 3.  Skilled labour. 
     Group 4.  Semi-and unskilled labour.

Marked differences between the groups were shewn.  The intellectual capacity was represented by figures as follows:—­

Group 1     125
Group 2     118
Group 3     107
Group 4      92

A further research of 548 children, grouped according to the occupation of their father, gave its results in terms of the percentage of children in each group who scored a mark higher than the median for the whole 548.  They are as follows:—­

Professional group      85%
Executive group         68%
Artisan group           41%
Labour group            39%

In the “Journal of Educational Psychology,” Vol.  IX, 1916, Mr. A.W.  Kornhauser gives evidence from the examination of 1,000 children drawn from five schools in Pittsburgh.

Schools A and B were attended by children of unskilled manual workers.

Schools C and D by children of skilled artisans and small shopkeepers.

School E by children of parents in very comfortable circumstances.

The results are tabulated as—­

     Retarded, i.e., below average. 
     Normal, i.e., average. 
     Advanced, i.e., above average.

| Retarded. | Normal. | Advanced. 
A } Manual workers        {|  45.2     | 47.1    |   7.7
B }                       {|  36.7     | 55.9    |   7.4
|           |         |
C } Artisans, etc.        {|  29.4     | 50.2    |  20.7
D }                       {|  28.8     | 50.2    |  19.5
|           |         |
E Most comfortable         |  12.7     | 62.7    |  24.6[A]

[Footnote A:  I am indebted to Professor McDougall’s book for information here given.]

These experiments all shew the trend of intelligence (and with it will power or power of concentration, and what we may call general capacity) to be more concentrated in the so-called higher grades of society, and to be less and less evident as we descend in the scale from skilled to unskilled workers.  It would, of course, be clear to all that the children of mentally deficient parents can only be a burden on the State or can rarely contribute anything of value to the common weal.