"We came over to see how you were getting on with that poison business, Dr. Markfield. Can you give us any news?"
Markfield indicated a notebook on his desk.
"I’ve got it out, I think. It’s all there; but I haven’t had time to write a proper report on it yet. It was——"
"Hyoscine?" Sir Clinton interrupted.
Markfield stared at him with evident appreciation.
"You’re quite right," he confirmed, with some surprise. "I suppose you’ve got private information."
The Chief Constable evaded the point.
"I’m asking this question only for our own information; you won’t be asked to swear to it in court. What amount of hysocine do you think was in the body, altogether? I mean, judging from the results you obtained yourself."
Markfield considered for a moment.
"I’m giving you a guess, but I think it’s fairly near the mark. I wouldn’t, of course, take my oath on it. But the very smallest quantity, judging from my results, would be somewhere in the neighbourhood of seven or eight milligrammes."
"Have you looked up anything about the stuff—maximum dose, and so forth?" Sir Clinton inquired.
"The maximum dose of hyoscine hydrobromide is down in the books as six-tenths of a milligramme—about a hundredth of a grain in apothecaries’ weights."
"Then she must have swallowed ten or twelve times the maximum dose," Sir Clinton calculated, after a moment or two of mental arithmetic.
He paused for a space, then turned again to Markfield.
"I’d like to see the hyoscine in your store here, if you can lay your hands on it easily."
Markfield made no objection.
"If you’d come in yesterday, the bottle would have been here, beside me. I’ve taken it back to the shelf now."
"I suppose you borrowed it to do a mixed melting-point?" Sir Clinton asked.
"Yes. When there’s only a trace of a stuff to identify, it’s the easiest method. But you seem to know something about chemistry?"
"About enough to make mistakes with, I’m afraid. It simply happened that someone described the mixed melting-point business to me once; and it stuck in my mind. Now suppose we look at this store of yours."
Markfield led them along a passage and threw open a door at the end.
"In here," he said.
"You don’t keep it locked?" Sir Clinton inquired casually, as he passed in, followed by the Inspector.
"No," Markfield answered in some surprise. "It’s the general chemical store for this department. There’s no point in keeping it locked. All our stuffs are here, and it would be a devilish nuisance if one had to fish out a key every time one wanted some chloroform or benzene. We keep the duty-free alcohol locked up, of course. That’s necessary under the Customs’ regulations."
Sir Clinton readily agreed.
"You’re all trustworthy people, naturally," he admitted, "It’s not like a place where you have junior students about who might play thoughtless tricks."
Markfield went over to one of the cases which lined the room, searched along a shelf, and took down a tiny bottle.
"Here’s the stuff," he explained, holding it out to the Chief Constable. "That’s the hydrobromide, of course—a salt of the alkaloid itself. This is the compound that’s used in medicine."
Now that he had got it, Sir Clinton seemed to have little interest in the substance. He handed it across to Flamborough who, after looking at it with would-be sagacity, returned it to Markfield.
"There’s just one other point that occurs to me," the Chief Constable explained, as Markfield returned the poison-bottle to its original place. "Have you, by any chance, got an old notebook belonging to young Hassendean on the premises? Anything of the sort would do."
The Inspector could make nothing of this demand and his face betrayed his perplexity as he considered it. Markfield thought for a few moments before replying, evidently trying to recall the existence of any article which would suit Sir Clinton’s purpose.
"I think I’ve got a rough notebook of his somewhere in my room," he said at last. "But it’s only a record of weighings and things like that. Would it do?"
"The very thing," Sir Clinton declared, gratefully. "I’d be much obliged if you could lay your hands on it for me now. I hope it isn’t troubling you too much."
It was evident from Markfield’s expression that he was as much puzzled as the Inspector; and his curiosity seemed to quicken his steps on the way back to his room. After a few minutes’ hunting, he unearthed the notebook of which he was in search and laid it on the table before Sir Clinton. Flamborough, familiar with young Hassendean’s writing, had no difficulty in seeing that the notes were in the dead man’s hand.
Sir Clinton turned over the leaves idly, examining an entry here and there. The last one seemed to satisfy him, and he put an end to his inspection. Flamborough bent over the table and was mystified to find only the following entry on the exposed leaf:
Weight of potash bulb = 50.7789 grs.
Weight of potash bulb + CO2 = 50.9825 grs.
Weight of CO2 = 0.2046 grs.
"By the way," said Sir Clinton casually, "do you happen to have one of your own notebooks at hand—something with the same sort of thing in them?"
Markfield, obviously puzzled, went over to a drawer and pulled out a notebook which he passed to the Chief Constable. Again Sir Clinton skimmed over the pages, apparently at random, and then left the second book open beside the first one. Flamborough, determined to miss nothing, examined the exposed page in Markfield’s notebook, and was rewarded by this:—
Weight of U-tube = 24.7792 gms.
Weight of U-tube + H2O = 24.9047 gms.
Weight of H2O = 0.1255gms.
"Damned if I see what he’s driving at," the Inspector said savagely to himself. "It’s Greek to me."
"A careless young fellow," the Chief Constable pronounced acidly. "My eye caught three blunders in plain arithmetic as I glanced through these notes. There’s one on this page here," he indicated the open book. "He seems to have been a very slapdash sort of person."
"An unreliable young hound!" was Markfield’s slightly intensified description. "It was pure influence that kept him here for more than a week. Old Thornton, who put up most of the money for building this place, was interested in him—knew his father, I think—and so we had to keep the young pup here for fear of rasping old Thornton’s feelings. Otherwise. . . ."
The gesture accompanying the aposiopesis expressed Markfield’s idea of the fate which would at once have befallen young Hassendean had his protector’s influence been withdrawn.
The Chief Constable appeared enlightened by this fresh information.
"I couldn’t imagine how you came to let him have the run of the place for so long," he confessed. "But, of course, as things were, it was evidently cheaper to keep him, even if he did no useful work. One can’t afford to alienate one’s benefactors."
After a pause, he continued, reverting apparently to an earlier line of thought:
"Let’s see. You made out that something like twelve times the normal dose of hyoscine had been administered?"
Markfield nodded his assent, but qualified it in words:
"That’s a rough figure, remember."
"Of course," Sir Clinton agreed. "As a matter of fact, the multiple I had in my mind was 15. I suppose it’s quite possible that some of the stuff escaped you and that your figure is an under-estimate?"
"Quite likely," Markfield admitted frankly. "I gave you the lowest figure, naturally—a figure I could swear to if it came to the point. As it’s a legal case, it’s safer to be under than over the mark. But quite probably, as you say, I didn’t manage to isolate all the stuff that was really present; and I wouldn’t deny that the quantity in the body may have run up to ten milligrammes or even slightly over it."