450 SECTIONAL TRANSACTIONS.—J. 
16. Miss E. L. G. Ross.—The Estimation of Vocational Fitness among 
Mental Defectives. 
In view of the increasing importance being attached to the provision of 
industrial colonies for the permanent care of the feeble-minded, an investigation 
was undertaken to estimate the reliability of various forms of tests which seemed 
to measure abilities making for efficiency in those occupations usually provided 
for defectives. About fifty institution cases of various ages and grades were 
taken as subjects and their standing in the various tests compared with their 
known industrial ability and learning capacity. Those temperamental factors 
which go towards social efficiency were studied on the basis of the Porteus 
Social Ratings Scale. 
17, Mr. F. Warrs.—The Present Condition of Industrial Psychology. 
18. Dr. A. R. Apenson.—A Plea for the Psychological Treatment of 
the Delinquent Child. 
There is an accumulating amount of reliable evidence that wrongdoing is 
largely bound up with morbid conditions of health. An important percentage 
of delinquents are mentally deficient. Insanity and epilepsy are important 
factors. It is found that a large number of delinquent children possess a 
‘neurotic’ constitution and psychological measures have succeeded in effecting 
considerable improvement where all other methods of treatment had more or 
less completely failed. One must also look for physiological irregularities, e.g. 
adenoids, tonsils, endocrinal insufficiency, but even in these cases psychological 
treatment should be used in conjunction with the other remedial measures. 
By far the best method of treatment is by psychological analysis. 
19. Miss E. M. BickersteruH.—Coloured Thinking. 
20. Mr. J. G. Taytor.—The Use of ‘ Retinal Rivalry’ for a Test of 
Colour Fatigue. 
The experiments described in this paper were carried out in connection with 
the study of colour-fatigue in industries such as paper-making, where accurate 
discrimination of colour-tints and shades may be required. It was known 
that prolonged stimulation of one retina or any colour affected retinal rivalry 
by reducing the proportion of that colour to its ‘rival’ in the alternating 
fields. Preliminary experiments showed that the proportion of red to blue 
after stimulation of one retina for three minutes with red varied in different 
subjects from .76 to .25 of the ‘normal’ proportion. 
In later experiments records of retinal rivalry were taken for thirty periods 
of one minute, separated by intervals of one minute. The colours used were 
red and blue, and the records were made by closing a key when red was 
dominant; except in a series of control experiments, when blue took the 
place of red in this respect. In the study of the records each half-minute 
was measured as well as each minute. 
The main argument of this paper was that a decrease in the rate of fluctua- 
tion may be taken as a measure of fatigue. The rate of fluctuation decreases 
from the first half of a minute to the second half, from the beginning to 
the end of an hour, from forenoon to afternoon, and sometimes from day 
to day. Introspection shows that slower fluctuation is accompanied subjectively 
by a feeling of fatigue and also by a decrease in the apparent purity of the 
colours. 
While change in the rate of fluctuation seems to be due mainly to fatigue, 
the total time per minute during which each colour is dominant seems to vary, 
partly with attention, partly with fatigue. Thus while the rate of fluctuation — 
usually falls steadily towards the end of each hour the total amount of red 
per minute rises and falls over periods varying from twenty-five minutes to 
forty minutes—which may be referred perhaps to the fluctuation of attention. 
In the control experiments the total amount of red per minute was much lower 
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