Several belated passers-by and a policeman watched me as though I were a house-breaker, and I felt like a fool, but at last, by perseverance and tact, I managed to capture a fairly good specimen of the species, and carried it in my arms to the laboratory with some profanity and many scratches.

XV

THE WEED OF MADNESS

In my absence Craig had set to work on a peculiar apparatus, as though he were distilling something from several of the cigarette stubs which he had been studying by means of the interferometer.

“Here’s your confounded cat,” I ejaculated, as I placed the unhappy feline in a basket and waited patiently until finally he seemed to be rewarded for his patient labours.  It was well along toward morning when he obtained in a test-tube a few drops of a colourless, odourless liquid.

“My interferometer gave me a clue,” he remarked, as he held the tube up with satisfaction.  “Without the tell-tale line in the spectrum which I was able to discover by its use I might have been hunting yet for it.  It is so rare that no one would ever have thought, offhand, I suppose, to look for it.  But here it is, I’m sure, only I wanted to be able to test it.”

“So you are not going to try it on yourself,” I said sarcastically, referring to his last experiment with a poison.  “This time you are going to make the cat the dog.”

“The cat will be better to test it on than a human being,” he replied, with a glance that made me wince, for, after his performance with the curare, I felt that once the scientific furore was on him I might be called upon to become an unwilling martyr to science.

It was with an air of relief, both for himself and my own peace and safety, that I saw him take the cat out of the basket and hold her in his arms, smoothing her fur gently, to quiet the feelings that I had severely ruffled.

Then with a dropper he sucked up a bit of the liquid from the test-tube.  I watched him intently as he let a small drop fall into the eye of the cat.

The cat blinked a moment, and I bent over to observe it more closely.

“It won’t hurt the cat,” he explained, “and it may help us.”

As I looked at the cat’s eye it seemed to enlarge, even under the glare of a light, shining forth, as it were, like the proverbial cat’s eye under a bed.

What did it mean?

Was there such a thing, I wondered hastily, as the drug of the evil eye?

“What have you found?” I queried.

“Something very much like the so-called ‘weed of madness,’ I think,” he replied slowly.

“The weed of madness?” I repeated.

“Yes.  It is similar to the Mexican toloache and the Hindu datura, which you must have heard about.”

I had heard of these weird drugs, but they had always seemed to be so far away and to belong rather to the atmosphere of civilizations different from New York.  Yet, I reflected, what was to prevent the appearance of anything in such a cosmopolitan city, especially in a case so unusual as that which had so far baffled even Kennedy’s skill?