The man’s self-mastery was almost superhuman.
He crossed to close the windows—to hide his face from me. Even that iron control had its breaking point. And suddenly the dead silence which fell with the shutting of the windows was broken by the buzzing of an insect.
I couldn’t see the thing, which evidently Sir Denis had disturbed, but it was flying about the place with feverish activity. Something else seemed to have arrested Sir Denis’s attention: he was staring down at the table.
“H’m!” he muttered. “Very queer!”
Then the noise of the busy insect evidently reached his ears. He turned in a flash and his expression was remarkable.
“What’s that, Sterling?” he snapped. “Do you hear it?”
“Clearly. There’s a gadfly buzzing about.”
“Gadfly—nothing! I have recently spent many hours in the laboratory of the School of Tropical Medicine. That’s why I’m here! Listen. Did you ever hear a gadfly that made that noise?”
His manner was so strange that it chilled me. I stood still, listening. And presently, in the sound made by that invisible, restless insect, I detected a difference. It emitted a queer sawing note. I stared across at Nayland Smith.
“You’ve been to Uganda,” he said. “Did you never hear it?”
At which moment, and before I had time to reply, I caught a glimpse of the fly which caused this peculiar sound. It was smaller than I had supposed. Narrowly missing the speaker’s head, it swooped down onto the table behind him, and settled upon something which lay there—something which had already attracted Sir Denis’s attention.
“Don’t move,” I whispered. “It’s just behind you.”
“Get it,” he replied, in an equally low voice; “a book, a roll of paper—anything; but for God’s sake don’t miss it....”
I took up a copy of the Gazette de Monte Carlo. One of poor Petrie’s hobbies was a roulette system which he had never succeeded in perfecting. I rolled it and stepped quietly forward.
Nayland Smith stood quite still. Beside him, my improvised swatter raised, I saw the insect distinctly. It had long, narrow, brownish wings and a curiously hairy head. In the very moment that I dashed the roll of paper down, I recognized the object upon which it had settled.
It was a spray of that purple-leaved drosophyllum, identi-cal except that it was freshly cut, with a fragment which I knew to be sealed in a tube somewhere in Petrie’s collection!
“Make sure,” said Sir Denis, turning.
I repeated the blow. Behind us, on the couch Petrie lay motionless. Sir Denis bent over the dead insect.
“Don’t you know what this is. Sterling?” he demanded.
“No. Flies are a bit outside my province. But I can tell you something about the purple leaves....”
Taking the roll of paper from me, he moved the dead fly further forward upon the polished table-top where direct light fall upon it; then:
“Hullo!” he exclaimed.
He snatched up a lens which lay near by and bent over the insect, peering down absorbedly.
I turned and looked towards the couch were Petrie lay, and I studied his haggard features. I could detect no evidence of life. The purple shadow showed like a bruise on his forehead;
but I thought that it had not increased.
Yet I believed he was doomed, already dying, and my thoughts jumped feverishly to that strange plant upon the table—and from the plant to the yellow face which so recently had leered at me out of the darkness.
Was it conceivable—could it be—that some human agency directed this pestilence?
I turned, looking beyond the bent, motionless figure of Nayland Smith, out into the dusk—and a desire to close the steel shutters suddenly possessed me.
This operation I completed without drawing a single comment from Sir Denis. But, as that menacing dusk was shut out, he stood upright and confronted me.
“Sterling,” he said, and there was something in his steady gaze which definitely startled me—”have you, as a botanist, ever come across a true genus-hybrid?”
“You mean a thing between a lily and a rose—or an oak growing apples?”
“Exactly.”
> “In the natural state, never—although some curious hybrids have been reported from time to time. But many freaks of this kind can be cultivated, of course. The Japanese are experts.”
“Cultivated? I agree. But nature, in my experience, sticks to the common law. Now here. Sterling—” he indicated the table—”lies an insect which, from the sound it made when flying, I took to be a tsetse fly——”
“A tsetse! Good heavens! Here?”
He smiled grimly.
“Well outside its supposed area,” he admitted, “and above its usual elevation. I thought you might have recognized its note, as you have travelled in the flybelt. However, I was right—up to a point. It definitely possesses certain characteristics ofglossina, the tsetse fly; notably the wings, which are typical. You see, I have been taking an intensive course on this subject! But can you imagine, Sterling, that it has the legs and head of an incredibly large sand-fly? The thing is a nightmare, an anachronism; it’s a sort of giant flying flea\”
His words awakened a memory. What had Petrie said to me, earlier in the evening?...that “even if Nature is turning topsy-turvy, I think I can puzzle her!...”
“Sir Denis,” I broke in, “I think you should know that Petrie found, in the blood of a patient, some similar freak—a sort of hybrid germ, which I lack the knowledge to describe to you. He found sleeping sickness and plague combined——”
“Good God!”
I thought that the lean, sun-baked face momentarily grew yet more angular.
“You know,” he interrupted, “that tsetse carries sleeping sickness? Sand-fly is suspect in several directions. But the rat-flea (and this is more like a flea than a sand-fly) is the proved cause of plague infection....Am I going mad?”
He suddenly crossed and bent over Petrie. He examined him carefully and in detail. The fact dawned upon me that Sir Denis Nayland Smith had more than a smattering of the medical art. I watched in silence while finally he took the temperature of the unconscious man.
“There’s no change,” he reported. “‘654’ seems already to have checked its progress. But this coma....Dare we hope?”
“I don’t know what to hope, or what to believe. Sir Denis!”
He nodded.
“Nor do I. The nature of my job has forced me to pick up some elements of medicine; but this is a specialist’s case....However, tell me about these leaves—the leaves which seemed to attract the fly....”
I told him briefly all that I knew of the insect-catching plant.
“The specimen which Petrie has preserved,” I concluded, “bears traces of human blood.”
Sir Denis suddenly grabbed the lens again and bent over the purple leaves on the table-top. A moment he looked, then turned.
“So does this!” he declared. “Fresh blood.”
I was dumb for a matter of seconds; then:
“The insect which I partly crushed?” I suggested.
He shook his head irritably.
“Quantity too great. These leaves have been sprayed with blood!”
“How, in heaven’s name, did they get here? And how did that damnable fly get here?”
He suddenly clapped his hands upon my shoulders arid stared at me fixedly.
“You’re a man of strong nerve. Sterling,” he said, “and so I can tell you. They were brought here. And—” he pointed to the still body on the couch—”for that purpose.”