66 TRANSACTIONS OF THE 
ient characteristics of the mirror-writers themselves. For 
instance, it was found that the ten who were chosen for 
intensive study, were found by the writer’s own objective 
tests to be extremely left-handed; the other thirty-two 
were reported by their teachers as being also markedly 
left-handed. This fact would imply a strange “motor 
imagery.”’ 
What really happens, it would seem, in case of such a 
child is that his first and early concepts of the writing act 
are awry; that is to say, that as he perceives others writ- 
ing in the conventional style with the right hand the imag- 
ery thus stimulated does not possess the optimum balance 
or association between the ‘‘visual” and the “‘motor’”’ ele- 
ments. While such a person does not reproduce with one 
hand the movements learned by the other, nevertheless 
the sight of those who do write normally is conceived of 
in ‘“‘motor’ terms, i.e., the most natural movements 
involved in a reproduction of the same. Furthermore, 
it is not difficult to see that such a child’s “‘scribble-period”’ 
may serve as a process of trial and error, by means of 
which he readily learns that the easiest form of movement 
is with the left hand and from right to left. In such cases 
as these, in which we also have extreme left-handedness, 
the period of ‘happening on to’’ the easier type of move- 
ment will naturally be very short, since it will take but a 
very few trials to reveal which is the easier form of move- 
ment. 
These, then, are the principal data available, with 
some of their limitations pointed out. Such practical 
school-room problems as the following still remain 
unsolved, however. If left-handedness is hereditary, up 
to what point is it safe to force left-handed children to 
become right-handed? What are the probabilities of 
inducing speech defects by changing handedness? Can 
a person who is naturally left-handed ever become as 
dexterous with his right hand? Growing out of these 
questions, however, there arises a more fundamental prob- 
lem of greater importance, viz: How may the native 
handedness of young children be detected or diagnosed? 
It was to this basic aspect of the problem in an attempt 
to derive a test, that the writer applied himself. 
In carrying out his investigation the writer proceeded 
