an.
Thoughts sweep across the human mind as sound currents sweep across
the aerials of a radio--"

"I told you!" Allen Parker turned a triumphant face to his wife.
"Pardon me, Herr Doktor! I have tried to convince Mrs. Parker that my
idea came from outside!"

* * * * *

"Exactly!" Dr. von Stein took no offense. "And a difference between
the mind and the radio set is that with the radio you tune in upon
whatever you choose, and when you choose. The mind is not under such
control, although it should be. It receives that to which it happens
to be open. Or that thought which has been intensified and
strengthened by having been received and entertained by other minds.
In India they say: 'Five thousand died of the plague and fifty
thousand died of fear.' Do you both follow me?"

It was unnecessary to ask. Betty sat on the edge of the couch, intent
upon every word. Parker, although more restrained, was equally
interested. Moreover he was delighted to have what he had felt
instinctively confirmed, in a way, by a man of science.

"Herbert Spencer said," continued the doctor, "that no thought, no
feeling, is ever manifested save as the result of a physical force.
This principle will before long be a scientific commonplace. And
Huxley predicted that we would arrive at a mechanical equivalent of
consciousness. But I will not attempt to bolster my position with
authorities. I know, and I can prove what I know.

"You, Mr. Parker, have been receiving some particularly annoying
thoughts which have been intensified, it may be, by others, or
another. Human will power can alter the rate of vibration of the line
of force, or etheric wave. So-called good thoughts have a high rate of
vibration, and those which are called bad ordinarily have a low rate.
Have you, perhaps, an enemy?"

"Not that I know of," replied Parker, in a low voice.

"Then it would follow that this is accidental."

* * * * *

"Good heavens! Do you mean to say that someone could do this to me
maliciously?"

"So far my experiments leave something to be desired," said Dr. von
Stein, without answering directly. "No doubt you are peculiarly
susceptible to thoughts which bear in any way on your work."

"But isn't there any help for it?" asked Betty. She was regarding her
husband with the eyes of a stranger.

"I believe I can do something for Mr. Parker."

There was a knock at the door. The doctor b