“His father’s a veterinary surgeon somewhere in the west country. I’m afraid that’s all I can tell you.”
It was enough. I recalled that veterinarians commonly used a footbath of copper sulfate to treat foot rot in sheep.
How remarkable, I thought, that six of the nine students on Staircase No. 3 had, in one way or another, direct connections to and perhaps some personal experience in the use of good old CuSO4. Knowledge or experience did not, of course, necessarily imply guilt, but it helped greatly in the process of elimination.
“Is Parker the son of a baker, a bookbinder, or a manufacturer of straw hats?” I asked Plaxton.
“Not so far as I know,” he said. “A music publisher, I believe.”
“And your own father?” I asked. It was a question I had been fearing to ask.
“He’s a Fleet Street journalist,” Plaxton answered. “He’s in jail for refusing to reveal his sources in the government pension scandal.”
“Of course,” I said. “I’m sorry.” I had seen the sensational stories in the illustrated news magazines: the fist-shaking crowds, the handcuffed prisoner.
“Tell me about Mr. Denning,” I went on, trying to get past the awkward moment. “Was he in the Service?”
“As a matter of fact, he was,” Plaxton replied. “He waded ashore at Castellazzo, in Sicily, in 1943, with the Eighth Army. Poor chap—he never really got over it. That’s why I felt so dreadful about—”
A great flare went off in my brain, and in that instant, everything became suddenly clear.
“Did he always wear long sleeves?” I interrupted.
“Funnily enough, he did,” Plaxton said, with an odd look. “Even in summer.”
“Then,” I said, “the only question left to ask is this: What did you do with the empty bottle?”
Plaxton’s face collapsed as if it were rubber.
“You know, then?” His voice was that of a ghost.
“Of course I know.” I tried my best to sound matter-of-fact. “The poor man was suffering from the Sicilian strain of sandfly fever.”
It was, I knew, a recurrence of kala-azar, or dumdum fever. Dogger, who knew at first hand a great deal about tropical diseases, had told me tales of the dreaded ailment caused by the bite of the phlebotomine sandfly, which feeds upon the blood of rodents. The fever, common in the Mediterranean, could manifest itself even after twenty years. The sores and lesions in the dead man’s nose should have alerted me at once, as should the prescription for Pentostam.
“You found him dead in the tub,” I told Plaxton. “He had suffered a heart attack while soaking himself in a bath of copper sulfate, whose crystals he had pinched from the chemistry lab to alleviate his sores. He may already have absorbed enough of the stuff to cause poisoning. An autopsy will tell.
“The evenness of the blue ring showed that there had been no thrashing around. The ring around his neck was constant and his face had not been immersed. Therefore, he either died in the tub, or was already dead when he was put there.
“You should have left the empty bottle, Plaxton. It was a careless oversight.
“Because of the god-awful row you’d had, you were still in a rage. You decided to hook him up to the battery, which you removed from Mr. Winter’s car, to make it look as if someone else—some unknown person, some passing stranger—had murdered him.”
“They’d never have believed me!” Plaxton blurted. “But how did you know?”
“By your irritated eyes,” I answered, “to begin with, and the hoarseness of your voice when you opened the door. Exposure to the steamy fumes of copper sulfate. You were there before the bathwater cooled.”
I didn’t feel any need to tell Plaxton about the theatrical greasepaint which Mr. Denning had been using for years to cover up his awful scales and lesions. In death, the poor man surely deserved at least a pinch of privacy.
“The police will soon be here,” I said. “I advise you to be straight with them. You needn’t mention my name.”
“Big help you’ve been,” Plaxton said, his voice dripping sarcasm.
“Thank you,” I replied, pretending not to notice. “As you requested, I’ve at least given you and your playmates excuses why you shouldn’t be charged with murder. You might be asked some awkward questions about interfering with a dead body, but that’s your problem—not mine.”
“No—look,” Plaxton said, coming to his senses. “Here, take this.”
And he pressed a five-pound note into my hand. I let it flutter to the ground, but he scooped it up and shoved it into my pocket.
It simply boggles the mind the way in which some people can turn on a sixpence. Or perhaps it was that I had misjudged Plaxton from the beginning. Pity is not always the best basis for trust.
As I got to my feet and began walking away across the grass, toward the old stone of Anson House, the new banknote crackled crisply in my pocket. It was, I realized with a secret thrill, the first pay I had ever received for professional consultation.
Gladys would be happy to see me. We would stop at Bert Archer’s garage on the way home and buy a fresh tin of bicycle oil.
It would be my treat.