“How am I going to feed it to him?” she asked. “The powder?”

“In a chocolate,” I said. “In a delicious little chocolate. It has to be small so that he’ll pop the whole thing in his mouth in one go.”

“And where pray do we get delicious little chocolates these days?” she asked. “You forget there’s been a war on.”

“That’s the whole point,” I said. “A. R. Woresley won’t have had a decent bit of chocolate since 1914. He’ll gobble it up.”

“But do you have any?”

“Right here,” I said. “Money can buy anything.” I opened a drawer and produced a box of chocolate truffles. Each was identical. Each was the size of a small marble. They were supplied to me by Prestat, the great chocolateers of Oxford Street, London. I took one of them and made a hole in it with a pin. I enlarged the hole a bit. I then used the head of the same pin to measure out one dose of Blister Beetle powder. I tipped this into the hole. I measured a second dose and tipped that in also.

“Hey!” Yasmin cried. “That’s two doses!”

“I know. I want to make absolutely sure Mr. Woresley delivers.”

“It’ll drive him round the twist.”

“He’ll get over it.”

“What about me?”

“I think you can take care of yourself,” I said. I pressed the soft chocolate together to seal up the hole. I then stuck a matchstick into the chocolate. “I’m giving you two chocolates,” I said. “One for you and one for him. His is the one with the match in it.” I put the chocolates in a paper bag and passed them over. We discussed at some length the plan of battle.

“Will he become violent?” she asked.

“Just a tiny bit.”

“And where do I get that thing you were talking about?”

I produced the thing in question. She examined it to make sure it was in good condition, then put it in her handbag.

“All set?”

“Yes,” she said.

“Don’t forget this one will be a dress rehearsal for all the others you’ll be doing later on. So learn all you can.”

“I wish I knew judo,” she said.

“You’ll be all right.”

I drove her back to Girton and saw her safely in through the gates of the college.

WE NOW MOVE FORWARD to five thirty in the afternoon of the following day. I myself was lying quite comfortably on the floor behind a row of wooden filing cabinets in A. R. Woresley’s laboratory. I had spent much of the day wandering casually in and out of the lab, reconnoitring the terrain and gradually easing the cabinets twenty inches away from the wall so that I could squeeze in behind them. I had also left a one-inch gap between two of the cabinets so that by looking through it I was able to get an excellent view along the whole length of the lab. A. R. Woresley always worked at the far end of the room, about twenty feet from where I was stationed. He was there now. He was fooling about with a rack of test tubes and a pipette and some blue liquid. He was not wearing his usual white coat today. He was in shirt-sleeves and a pair of grey flannels. There was a knock on the door.

“Come in!” he called out, not looking up.

Yasmin entered. I had not told her I was going to be watching. Why should I? But a general must always keep an eye on his troops during battle. My girl looked ravishing in a cotton print dress that fitted tightly around her superstructure, and as she came into the room there came with her that elusive aura of lust and lechery that followed her like a shadow wherever she went.

“Mr. Woresley?”

“Yes, I’m Woresley,” he said, still not looking up. “What do you want?”

“Please forgive me for barging in on you like this, Mr. Woresley,” she said. “I’m not a chemist. I’m actually a biology student. But I’ve run up against a rather difficult problem which is more chemical than biological. I’ve asked around all over the place but no one seems able to give me the answer. They all referred me to you.”

“They did, did they,” A. R. Woresley said, sounding pleased. He went on carefully measuring out blue liquid from a beaker into the test tubes with his pipette. “Just let me finish this,” he added. Yasmin stood still, waiting, sizing up the victim.

“Now, my dear,” A. R. Woresley said, laying down the pipette and turning round for the first time. “What was it you—” He stopped dead in mid-sentence. His mouth dropped open and his eyes became as large and round as half-crowns. Then the tip of his red tongue appeared underneath the bristles of his nicotine moustache and began sliding wetly over his lips. For a man who had seen little else but Girton girls and his own diabolic sister for years on end, Yasmin must have appeared before him like the creation, the first morning, the spirit moving over the waters. But he recovered quickly.

“You had something to ask me, my dear?”

Yasmin had prepared her question brilliantly. I have forgotten precisely how it went, but it dealt with a situation where chemistry (his subject) and biology (her subject) became intertwined in a most complex manner, and where a deep knowledge of chemistry was required in order to unravel the problem. The answer, as she had so shrewdly calculated, would take at least nine minutes to deliver, probably more.

“A fascinating question,” A. R. Woresley said. “Let me see how best to answer it for you.” He crossed to a long blackboard fixed to the wall of the lab. He picked up a piece of chalk.

“Would you like a chocolate?” Yasmin said. She had the paper bag in her hand and when A. R. Woresley turned round, she popped one into her own mouth. She took the second chocolate from the bag and held it toward him in her fingertips.

“My goodness gracious me!” he burbled. “What a treat!”

“Delicious,” she said. “Try it.”

A. R. Woresley took it and sucked it and rolled it round in his mouth and chewed it and finally swallowed it. “Glorious,” he said. “How very kind of you.”

At the moment when the chocolate went down his gullet, I noted the time on my watch. I saw Yasmin doing exactly the same thing. Such a sensible girl. A. R. Woresley was standing at the blackboard giving a long exposition with many splendid chemical formulae written in chalk. I didn’t listen to it. I was counting the minutes passing by. So was Yasmin. She hardly took her eyes from the watch on her wrist.

Seven minutes gone by . . .

Eight minutes . . .

Eight minutes and fifty seconds . . .

Nine minutes! And dead on time, the hand that held the chalk against the blackboard suddenly stopped writing. A. R. Woresley went rigid.

“Mr. Woresley,” Yasmin said brightly, timing it to perfection, “I wonder if you’d mind giving me your autograph. You are the only science lecturer whose autograph I still don’t have for my collection.” She was holding out a pen and a sheet of chemistry department notepaper.

“What’s that?” he stammered, putting one hand into his trouser pocket before turning round to face her.

“Just there,” Yasmin said, placing a finger halfway down the sheet as I had instructed her. “Your autograph. I collect them. I shall treasure yours more than any of the others.”

In order to take the pen, A. R. Woresley had to remove his hand from the pocket. It was a comical sight. The poor man looked as though he had a live snake in his trousers. And now he was beginning to bounce up and down on his toes.

“Just there,” Yasmin said, keeping her finger on the notepaper. “Then I shall paste it in my autograph book along with all the others.”

With his mind fogged by gathering passions, A. R. Woresley signed. Yasmin folded the paper and put it in her purse. A. R. Woresley clutched the edge of the wooden lab bench with both hands. He started rocking about all over the place as if the whole building were in a storm at sea. His forehead was damp with sweat. I reminded myself that he had had a double dose. I think Yasmin was reminding herself of the same thing. She took a couple of paces backwards and braced herself for the coming onslaught.