378 SECTIONAL TRANSACTIONS.—J. 
the collecting-centre for the various Borstal institutions. Recommendations 
were drawn up for each boy, but these were forwarded to the institutions only 
for alternate boys. 'The remainder formed a control group, and were 
allocated to their work-parties by their housemasters in the usual way. 
Of those who were put into parties judged suitable for them by the National 
Institute, 69°5 per cent. were successful. Of those who were put into 
parties judged suitable for them by their housemasters, 45:6 per cent. 
were successful. This difference is statistically significant. A survey of 
the National Institute’s ‘ failures ’ shows clearly the importance of the part 
which should be played in vocational guidance by the study of temperament. 
Monday, September 10. 
Dr. L. S. PENRosE.—The inheritance of mental ability (10.0). 
The intelligence of persons related in various degrees to mentally defective 
patients was ascertained. All the individuals concerned were tested by 
standard intelligence tests. For purposes of comparison a method of 
obtaining a mental ratio had to be evolved, which was valid for all ages, 
juvenile and adult. 
The following results were obtained from the investigation : 
(1) The mean intelligence of the relatives is higher than the mean intelli- 
gence of the defectives themselves and is reasonably close to the expected 
value inferred from the law of ancestral regression. 
(2) There is no direct correlation between mentality of patient and 
mentality of relative. 
It is concluded from (1) that multifactorial hereditary influence plays a 
large part in determining intelligence. On the other hand, it is concluded 
from (2) that there exist variations in intelligence, of considerable magni- 
tude, which are due to non-genetic causes. 
The problem of the relative importance of environment and heredity in 
determining mental ability can be further studied by comparing half sibs 
with the children of patients’ full sibs. 
Joint Discussion with Section L (Education, q. v.) on Some aspects 
of psychological and child guidance clinics (11.0). 
AFTERNOON. 
(Section meeting in two divisions.) 
Division 1. 
Dr. R. W. Pickrorp.—The group psychology of the Barbizon painters (2.0). 
The Barbizon painters formed a group with a definite life-history in the 
middle of the nineteenth century. ‘The exhibition of English naturalistic 
landscape paintings in Paris stimulated a latent reaction against the hardened 
classical tradition. ‘This reaction, including the Barbizon movement, was 
an expression of the increasingly bourgeois public. Corot, the first of the 
Barbizon painters, was but mildly reactive, and retained classical affinities. 
Rousseau and Millet followed, reacting violently. Other members were 
non-classical from the start. After somewhat independent reactions, these 
painters formed a group. ‘They were intimately interested in Barbizon and 
