congenial idleness.  Strange to say, Hilda’s prophecy came true.  Zuleika settled herself down comfortably in the Professor’s easy chair and fell into a sound sleep from which there was no awaking; while Roxana met fate on the tiger-skin she loved, coiled up in a circle, and passed from this life of dreams, without knowing it, into one where dreaming is not.  Sebastian noted the facts with a quiet gleam of satisfaction in his watchful eye, and explained afterwards, with curt glibness to the angry matron, that her favourites had been “canonised in the roll of science, as painless martyrs to the advancement of physiology.”

The weasels, on the other hand, with an equal dose, woke up after six hours as lively as crickets.  It was clear that carnivorous tastes were not the whole solution, for Roxana was famed as a notable mouser.

“Your principle?” Sebastian asked our sibyl, in his brief, quick way.

Hilda’s cheek wore a glow of pardonable triumph.  The great teacher had deigned to ask her assistance.  “I judged by the analogy of Indian hemp,” she answered.  “This is clearly a similar, but much stronger, narcotic.  Now, whenever I have given Indian hemp by your direction to people of sluggish, or even of merely bustling temperament, I have noticed that small doses produce serious effects, and that the after-results are most undesirable.  But when you have prescribed the hemp for nervous, overstrung, imaginative people, I have observed that they can stand large amounts of the tincture without evil results, and that the after-effects pass off rapidly.  I who am mercurial in temperament, for example, can take any amount of Indian hemp without being made ill by it; while ten drops will send some slow and torpid rustics mad drunk with excitement—­drive them into homicidal mania.”

Sebastian nodded his head.  He needed no more explanation.  “You have hit it,” he said.  “I see it at a glance.  The old antithesis!  All men and all animals fall, roughly speaking, into two great divisions of type:  the impassioned and the unimpassioned; the vivid and the phlegmatic.  I catch your drift now.  Lethodyne is poison to phlegmatic patients, who have not active power enough to wake up from it unhurt; it is relatively harmless to the vivid and impassioned, who can be put asleep by it, indeed, for a few hours more or less, but are alive enough to live on through the coma and reassert their vitality after it.”

I recognised as he spoke that this explanation was correct.  The dull rabbits, the sleepy Persian cats, and the silly sheep had died outright of lethodyne; the cunning, inquisitive raccoon, the quick hawk, and the active, intense-natured weasels, all most eager, wary, and alert animals, full of keenness and passion, had recovered quickly.

“Dare we try it on a human subject?” I asked, tentatively.

Hilda Wade answered at once, with that unerring rapidity of hers:  “Yes, certainly; on a few—­the right persons. I, for one, am not afraid to try it.”