write his signature. Suddenly it was noticed that there were no maps
on the walls. But since according to popular ideas it is not possible
to think of a general without maps, a few were placed in position for
the picture, and removed soon afterwards." [Footnote: _Op. cit._,
p. 99.]

The only feeling that anyone can have about an event he does not
experience is the feeling aroused by his mental image of that event.
That is why until we know what others think they know, we cannot truly
understand their acts. I have seen a young girl, brought up in a
Pennsylvania mining town, plunged suddenly from entire cheerfulness
into a paroxysm of grief when a gust of wind cracked the kitchen
window-pane. For hours she was inconsolable, and to me incomprehensible.
But when she was able to talk, it transpired that if a window-pane
broke it meant that a close relative had died. She was, therefore,
mourning for her father, who had frightened her into running away
from home. The father was, of course, quite thoroughly alive as a
telegraphic inquiry soon proved. But until the telegram came, the
cracked glass was an authentic message to that girl. Why it was
authentic only a prolonged investigation by a skilled psychiatrist
could show. But even the most casual observer could see that the girl,
enormously upset by her family troubles, had hallucinated a complete
fiction out of one external fact, a remembered superstition, and a
turmoil of remorse, and fear and love for her father.

Abnormality in these instances is only a matter of degree. When an
Attorney-General, who has been frightened by a bomb exploded on his
doorstep, convinces himself by the reading of revolutionary literature
that a revolution is to happen on the first of May 1920, we recognize
that much the same mechanism is at work. The war, of course, furnished