“You will remember, Watson,” he remarked one afternoon,“that there is a single common point of resemblance in thevarying reports which have reached us. This concerns the effectof the atmosphere of the room in each case upon those whohad first entered it. You will recollect that Mortimer Tregennis,in describing the episode of his last visit to his brother’s house,remarked that the doctor on entering the room fell into a chair?
You had forgotten? Well I can answer for it that it was so. Now,you will remember also that Mrs. Porter, the housekeeper, toldus that she herself fainted upon entering the room and hadafterwards opened the window. In the second case—that ofMortimer Tregennis himself—you cannot have forgotten thehorrible stuffiness of the room when we arrived, though theservant had thrown open the window. That servant, I found uponinquiry, was so ill that she had gone to her bed. You will admit,Watson, that these facts are very suggestive. In each case thereis evidence of a poisonous atmosphere. In each case, also, thereis combustion going on in the room—in the one case a fire, inthe other a lamp. The fire was needed, but the lamp was lit—as acomparison of the oil consumed will show—long after it was broaddaylight. Why? Surely because there is some connection betweenthree things—the burning, the stuffy atmosphere, and, finally, themadness or death of those unfortunate people. That is clear, is it not?”
“It would appear so.”
“At least we may accept it as a working hypothesis. We willsuppose, then, that something was burned in each case whichproduced an atmosphere causing strange toxic effects. Very good.
In the first instance—that of the Tregennis family—this substancewas placed in the fire. Now the window was shut, but the firewould naturally carry fumes to some extent up the chimney.
Hence one would expect the effects of the poison to be less thanin the second case, where there was less escape for the vapour. Theresult seems to indicate that it was so, since in the first case onlythe woman, who had presumably the more sensitive organism, waskilled, the others exhibiting that temporary or permanent lunacywhich is evidently the first effect of the drug. In the second casethe result was complete. The facts, therefore, seem to bear out thetheory of a poison which worked by combustion.
“With this train of reasoning in my head I naturally lookedabout in Mortimer Tregennis’s room to find some remains of thissubstance. The obvious place to look was the talc shelf or smokeguardof the lamp. There, sure enough, I perceived a number offlaky ashes, and round the edges a fringe of brownish powder,which had not yet been consumed. Half of this I took, as you saw,and I placed it in an envelope.”
“Why half, Holmes?”
“It is not for me, my dear Watson, to stand in the way of theofficial police force. I leave them all the evidence which I found.
The poison still remained upon the talc had they the wit to findit. Now, Watson, we will light our lamp; we will, however, take theprecaution to open our window to avoid the premature deceaseof two deserving members of society, and you will seat yourselfnear that open window in an armchair unless, like a sensible man,you determine to have nothing to do with the affair. Oh, you willsee it out, will you? I thought I knew my Watson. This chair I willplace opposite yours, so that we may be the same distance fromthe poison and face to face. The door we will leave ajar. Each isnow in a position to watch the other and to bring the experimentto an end should the symptoms seem alarming. Is that all clear?
Well, then, I take our powder—or what remains of it—from theenvelope, and I lay it above the burning lamp. So! Now, Watson,let us sit down and await developments.”
They were not long in coming. I had hardly settled in mychair before I was conscious of a thick, musky odour, subtle andnauseous. At the very first whiff of it my brain and my imaginationwere beyond all control. A thick, black cloud swirled before myeyes, and my mind told me that in this cloud, unseen as yet, butabout to spring out upon my appalled senses, lurked all that wasvaguely horrible, all that was monstrous and inconceivably wickedin the universe. Vague shapes swirled and swam amid the darkcloud-bank, each a menace and a warning of something coming,the advent of some unspeakable dweller upon the threshold,whose very shadow would blast my soul. A freezing horror tookpossession of me. I felt that my hair was rising, that my eyeswere protruding, that my mouth was opened, and my tongue likeleather. The turmoil within my brain was such that somethingmust surely snap. I tried to scream and was vaguely aware of somehoarse croak which was my own voice, but distant and detachedfrom myself At the same moment, in some effort of escape, Ibroke through that cloud of despair and had a glimpse of Holmes’sface, white, rigid, and drawn with horror—the very look which Ihad seen upon the features of the dead. It was that vision whichgave me an instant of sanity and of strength. I dashed from mychair, threw my arms round Holmes, and together we lurchedthrough the door, and an instant afterwards had thrown ourselvesdown upon the grass plot and were lying side by side, consciousonly of the glorious sunshine which was bursting its way throughthe hellish cloud of terror which had girt us in. Slowly it rose fromour souls like the mists from a landscape until peace and reason hadreturned, and we were sitting upon the grass, wiping our clammyforeheads, and looking with apprehension at each other to mark thelast traces of that terrific experience which we had undergone.
“Upon my word, Watson!” said Holmes at last with an unsteadyvoice, “I owe you both my thanks and an apology. It was anunjustifiable experiment even for one’s self, and doubly so for afriend. I am really very sorry.”
“You know,” I answered with some emotion, for I have neverseen so much of Holmes’s heart before, “that it is my greatest joyand privilege to help you.”