“Of course, of course,” cried the other, “you have my permission and my best wishes for success.  I can see no possible objection, but—­”

“But what?”

“I pray to Heaven you will not undertake this experiment alone, will you?”

“Oh, dear, no; not alone.”

“You will take a companion with good nerves, and reliable in case of disaster, won’t you?”

“I shall bring two companions,” the doctor said.

“Ah, that’s better.  I feel easier.  I am sure you must have among your acquaintances men who—­”

“I shall not think of bringing men, Mr. Pender.”

The other looked up sharply.

“No, or women either; or children.”

“I don’t understand.  Who will you bring, then?”

“Animals,” explained the doctor, unable to prevent a smile at his companion’s expression of surprise—­“two animals, a cat and a dog.”

Pender stared as if his eyes would drop out upon the floor, and then led the way without another word into the adjoining room where his wife was awaiting them for tea.

II

A few days later the humorist and his wife, with minds greatly relieved, moved into a small furnished house placed at their free disposal in another part of London; and John Silence, intent upon his approaching experiment, made ready to spend a night in the empty house on the top of Putney Hill.  Only two rooms were prepared for occupation:  the study on the ground floor and the bedroom immediately above it; all other doors were to be locked, and no servant was to be left in the house.  The motor had orders to call for him at nine o’clock the following morning.

And, meanwhile, his secretary had instructions to look up the past history and associations of the place, and learn everything he could concerning the character of former occupants, recent or remote.

The animals, by whose sensitiveness he intended to test any unusual conditions in the atmosphere of the building, Dr. Silence selected with care and judgment.  He believed (and had already made curious experiments to prove it) that animals were more often, and more truly, clairvoyant than human beings.  Many of them, he felt convinced, possessed powers of perception far superior to that mere keenness of the senses common to all dwellers in the wilds where the senses grow specially alert; they had what he termed “animal clairvoyance,” and from his experiments with horses, dogs, cats, and even birds, he had drawn certain deductions, which, however, need not be referred to in detail here.

Cats, in particular, he believed, were almost continuously conscious of a larger field of vision, too detailed even for a photographic camera, and quite beyond the reach of normal human organs.  He had, further, observed that while dogs were usually terrified in the presence of such phenomena, cats on the other hand were soothed and satisfied.  They welcomed manifestations as something belonging peculiarly to their own region.