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.
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
