Sherry was poured with an undercurrent of seriousness that Tuesday evening. The Old Man rambled on about his experiences in medical school and the state of their knowledge of physiology and biochemistry in those days. Lurking below the surface was the message that one must be ready to change old habits, theories and courses of action.

     At dinner, Margaret had me describe my cohort of first-year students and showed surprise at the high proportion of girls. No young ladies went into science in her days. A lady’s place was tending hearth and home. But she had been a "sub-lieutenant" in the searchlight corps north of London during the Second World War. "’Twas many a time the sirens wailed but never once did the Jerries fly over my sector. We would have singed their tail feathers with our hot lights, we would have! Then the boys from the flack company would have shot their tail feathers off!"

     To please her, I saluted the great English thinkers, Hume, Hobbes, Locke, Toynbee, Huxley, and the great ‘doers’ like Disraeli and Churchill.

     "Yes, we have always had a sense of mission, haven’t we, Wessie?" He nodded. "When we first came here, I told Wessie that it was like being in civil service in India, with the heat and with so many dark-skinned people. Not that the Americans were all coloured, mind you."

     She complained about the lack of cultural amenities in Miami. "It was as if we were always giving culture but never receiving it. But I do feel that through the years we have left some sort of impression on the native people. Don’t you, Wessie?"

     "Yes," said the Old Man. "I should say that we did, although I would rather agree with Orwell that they can never really be changed. The migrations, the street drugs and the carnal breeding are much stronger influences than a few human good examples. One needs a much more controlled environment for a better sort of thing. Like England."

     For some reason I became irritated, and I countered, "But England has its share of problems — soccer rowdies, skinheads and teenagers joyriding in stolen cars."

     "That’s all in the North," the Old Man said, coming to the defense of The Realm. "And much is due to American influence, with their fascination for motor cars, rock and roll music, drugs and the like."

     "Well," I said, feeling a little argumentative and cocky, "it was before my time, but my folks told me that the original American rock and roll was pretty harmless. My dad said it was the Beatles and the Rolling Stones who brought in the drugs. He also told me that because the Beatles made so much money with their records and LSD lyrics, the Queen knighted them."

     The Old Man’s chin stiffened.

     "No. It was the Order of the Empire. A tragic mistake, and I know many a chap who turned back his medal when that was announced."

     Margaret returned to the subject of "lady scientists," asking me if I had found any of them particularly attractive. I told her about Rebecca, my "lady medical student" friend. Then Margaret committed a faux pas, declaring that Levis was a strange name, and could it be Jewish?

     The Old Man and I "removed" quickly to the balcony.

     "You mustn’t mind Margaret, she sometimes . . ."

     "It’s quite all right," I said. "What I’d really like to know is how you are coming with your assays.

     "I am sorry to say, Benjamin, that the picture is not so rosy. In fact, it would appear to be a complete bust."

     "You mean that you can’t assay blood specimens with sufficient sensitivity. Perhaps I could help."

     "No, the assays went along quite fine and dandy. We had sufficient sensitivity to assay blood concentrations lower than ten percent of the LD50 for each of the compounds — less than ten percent of what was necessary to kill Cooper. If any of those thirteen compounds had been the cause of death, they would have been detected."

     I was flabbergasted. As his message sank in, I was overwhelmed with dejection. Had I picked the wrong compounds? Or the wrong man? How in hell could I do a better job than I’d done already? And who else should I investigate?

     "What I gave you was a short list," I protested. "Maybe it was one of the toxins on the long list."

     "Benjamin, I am afraid that our resources are too limited to look under every rock, so to speak. Our funds, our personnel and the quantity of original sample are not limitless."

     Sensing my disappointment, he tried to console me with a nautical analogy, advising me to take another tack. But I felt like I was navigating in the foggy Arctic Sea north of Hudson’s Bay with winter coming on, the compass not working and the ice floes closing in. And I was sick and tired of communicating in double-entendre.

     "Which prof should I be looking at?"

     "I cannot say."

     "You’ll have to give me more hard information. Give me the real cause of death . . . I’m sorry to be getting upset . . . I mean the ‘cause of the demise.’ Give me the symptoms. I simply can’t pull the whole thing out of thin air."

     "Well, Ben, I had tacitly agreed with the neurotoxin theory since the nerves and the heart are, to be sure, the most sensitive targets in the human body. But you will remember from our initial discussion that there were other very singular observations. For example, there was a most curious general swelling of the tongue — the purple color and a generalized disseminated arterial thrombosis. It would appear that almost every small artery of the body contained blood clots. This is not the sort of thing one finds in a garden-variety cadaver — no pun intended. And there was hyperkalemia. One doesn’t find such high blood potassium, particularly in sudden death by heart failure. It was as if potassium had leaked from every cell in his body."

     "Do you have any idea what sort of agent can cause this type of thing?"

     "Well, the thrombosis indicates a derangement of the clotting system . . . activation of the blood platelets. One exogenous source would be endotoxin from bacterial infection in the blood. Naturally, we checked this out and found none. But there are many other proteins and glycoproteins which can cause these symptoms. But how could toxin proteins be administered when we didn’t find any needle tracks?"

     "What other symptoms should I concentrate on?"

     "There were also many indications of an allergic shock which could be triggered by a massive dose of histamine. However, he could not have received a lethal dose of histamine by mouth, because it will cause massive stomach acid secretion and immediate vomiting. I’m afraid that I shouldn’t say more than this."

     I expressed my regrets for wasting his time by not doing a better job.

     "Ben, the time was not wasted," he said soothingly. "You have worked systematically, checking the most obvious first. Your investigation did make some progress by eliminating the possible."

     "And whatever is left over, no matter how strange, has to be the truth. Is that correct, Mr. Holmes?"

     "Why, yes!"

     "But I don’t like playing Watson — always one step behind you."

     "I’m sorry, Benjamin, but I’m in just as thick a fog as you. You’ll just have to buck up and keep a stiff upper lip. Or as the old Cockney expression goes, ‘Keep your pecker to the grindstone’."

     "Well, just to be sure that I’m not wasting blood on the wrong grindstone, could you please answer one question?"

     "Possibly."

     "Were Manson and Ledbetter present at the Last Supper?"

     "Manson wasn’t; Ledbetter was."

     As I said goodnight to Dr. Westley, I tried my damnedest to "buck up."

     "One of my Swarthmore profs used to say that the tragedy of science was a beautiful theory destroyed by an ugly fact."

     "Yes, he was quoting Huxley. Thomas Huxley, of course."

     So the Old Man couldn’t resist one-upping me, even now. Alone inside the elevator, I kicked the door. So much work still ahead of me. One prof down and several more to go. And it wasn’t clear who was the next candidate.

     Damn this investigation! It was just like a damned science project — starts out looking simple but turns out complex and downright bewildering. I would have to construct a new list with all 12 suspects.

     It took me a long time to fall asleep, and I woke up early. I had to be sure I could eliminate Ashton. At my carrel in the library, hunched over my computer, I scoured Ashton’s order files for any agent which would give thrombosis or histamine shock. And I found nothing in his files. Sure, he had lots of orders for crude venom that contained enzymes which would chomp on clotting factors in the blood and initiate thrombosis. But he would have to inject them. And Cooper had not been injected.

     Or did Ashton have specialized knowledge that would allow him to deliver protein toxins by mouth? How could I question him without creating suspicion? I remembered the old television detective, Columbo.

     I stowed the computer in my locker, went to Ashton’s lab and puttered around, as if tidying up odds and ends. Finally, he noticed me.

     "Mr. Candidi, I read your report over the weekend. Nice piece of work. Actually, it was the nicest piece of work I’ve seem from a rotation in the last ten years."

     "Well, thank you, Dr. Ashton."

     He sounded and looked sincere. The bow tie was gone, perhaps in anticipation of Thanksgiving vacation.

     "Yes, you seem to have mastered the material very quickly. I think you could do quite well in neuroscience."

     Did he mean this, or was I just thirsting for praise? He looked me right in the eye this time instead of gazing past me.

     Then I put on my Columbo act, asking dumb questions about how poisonous were the toxins in the lab and asking about the warnings on the package inserts and how they could be lethal to a human being. He listened to this patiently, showing no mistrust or agitation. I laid in a long pause, trying to create tension. Then I blurted out the question.

     "But if you put it into a man’s bloodstream it would be sudden death!"

     I couldn’t have asked it any more directly. We were eyeball to eyeball, and I gave him a dumb stare. He stared back — no pupil dilation, no blink.

     "Mr. Candidi, what you say is absolutely true but — "

     "So what keeps a cobra from killing itself with all that poison in its glands?" I blurted out.

     A guilty man should have experienced an explosive release of tension. But Ashton showed no reaction to my dumb question — no nervous laugh, no sign of relief, no change of posture. He told me the glands secrete the poison into poison sacs, which are lined with an epithelial layer that acts as a barrier, just like the skin. The poison can’t cross the epithelial layer into the blood.

     I asked him a lot more "innocent" questions, and he answered them all without suspicion or emotion. Finally, he glanced at his watch and excused himself.

     Ashton’s last words were a thinly veiled invitation for me to come back and do my dissertation research with him.

     Call it 20-20 hindsight. Ashton couldn’t have been the murderer. He was too well focussed and self-contained. It was written all over him, even in his handwriting. He’d probably walled off Cooper, like the snake’s poison sac walls off the venom. He’d probably talked to the Dean. He couldn’t have killed Cooper if he’d wanted to. He couldn’t even find sodium chloride in his own laboratory.