mountain, people, strong, fire, them, flame.”
“It doesn’t look very promising at first sight,” I remarked. “What is the Professor’s theory?”
“His theory—provisionally, of course—is that the words form the message, and the groups of letters represent mere filled-up spaces between the words.”
“But surely,” I protested, “that would be a very transparent device.”
Thorndyke laughed. “There is a childlike simplicity about it,” said he, “that is highly attractive—but discouraging. It is much more probable that the words are dummies, and that the letters contain the message. Or, again, the solution may lie in an entirely different direction. But listen! Is that cab coming here?”
It was. It drew up opposite our chambers, and a few moments later a brisk step ascending the stairs heralded a smart rat-tat at our door. Flinging open the latter, I found myself confronted by a well-dressed stranger, who, after a quick glance at me, peered inquisitively over my shoulder into the room.
“I am relieved, Dr. Jervis,” said he, “to find you and Dr. Thorndyke at home, as I have come on somewhat urgent professional business. My name,” he continued, entering in response to my invitation, “is Barton, but you don’t know me, though I know you both by sight. I have come to ask you if one of you—or, better still, both—could come tonight and see my brother.”
“That,” said Thorndyke, “depends on the circumstances and on the whereabouts of your brother.”
“The circumstances,” said Mr. Barton, “are, in my opinion, highly suspicious, and I will place them before you—of course, in strict confidence.”
Thorndyke nodded and indicated a chair.
“My brother,” continued Mr. Barton, taking the profferred seat, “has recently married for the second time. His age is fifty-five, and that of his wife twenty-six, and I may say that the marriage has been—well, by no means a success. Now, within the last fortnight, my brother has been attacked by a mysterious and extremely painful affection of the stomach, to which his doctor seems unable to give a name. It has resisted all treatment hitherto. Day by day the pain and distress increase, and I feel that, unless something decisive is done, the end cannot be far off.”
“Is the pain worse after taking food?” inquired Thorndyke.
“That’s just it!” exclaimed our visitor. “I see what is in your mind, and it has been in mine, too; so much so that I have tried repeatedly to obtain samples of the food that he is taking. And this morning I succeeded.” Here he took from his pocket a wide-mouthed bottle, which, disengaging from its paper wrappings, he laid on the table. “When I called, he was taking his breakfast of arrowroot, which he complained had a gritty taste, supposed by his wife to be due to the sugar. Now I had provided myself with this bottle, and, during the absence of his wife, I managed unobserved to convey a portion of the arrowroot that he had left into it, and I should be greatly obliged if you would examine it and tell me if this arrowroot contains anything that it should not.”
He pushed the bottle across to Thorndyke, who carried it to the window, and, extracting a small quantity of the contents with a glass rod, examined the pasty mass with the aid of a lens; then, lifting the bell-glass cover from the microscope, which stood on its table by the window, he smeared a small quantity of the suspected matter on to a glass slip, and placed it on the stage of the instrument.
“I observe a number of crystalline particles in this,” he said, after a brief inspection, “which have the appearance of arsenious acid.”
“Ah!” ejaculated Mr. Barton, “just what I feared. But are you certain?”
“No,” replied Thorndyke; “but the matter is easily tested.”
He pressed the button of the bell that communicated with the laboratory, a summons that brought the laboratory assistant from his lair with characteristic promptitude.
“Will you please prepare a Marsh’s apparatus, Polton,” said Thorndyke.
“I have a couple ready, sir,” replied Polton.
“Then pour the acid into one and bring it to me, with a tile.”
As his familiar vanished silently, Thorndyke turned to Mr. Barton.
“Supposing we find arsenic in this arrowroot, as we probably shall, what do you want us to do?”
“I want you to come and see my brother,” replied our client.
“Why not take a note from me to his doctor?”
“No, no; I want you to come—I should like you both to come—and put a stop at once to this dreadful business. Consider! It’s a matter of life and death. You won’t refuse! I beg you not to refuse me your help in these terrible circumstances.”
“Well,” said Thorndyke, as his assistant reappeared, “let us first see what the test has to tell us.”
Polton advanced to the table, on which he deposited a small flask, the contents of which were in a state of brisk effervescence, a bottle labelled “calcium hypochlorite,” and a white porcelain tile. The flask was fitted with a safety-funnel and a glass tube drawn out to a fine jet, to which Polton cautiously applied a lighted match. Instantly there sprang from the jet a tiny, pale violet flame. Thorndyke now took the tile, and held it in the flame for a few seconds, when the appearance of the surface remained unchanged save for a small circle of condensed moisture. His next proceeding was to thin the arrowroot with distilled water until it was quite fluid, and then pour a small quantity into the funnel. It ran slowly down the tube into the flask, with the bubbling contents of which it became speedily mixed. Almost immediately a change began to appear in the character of the flame, which from a pale violet turned gradually to a sickly blue, while above it hung a faint cloud of white smoke. Once more Thorndyke held the tile above the jet, but this time, no sooner had the pallid flame touched the cold surface of the porcelain, than there appeared on the latter a glistening black stain.
“That is pretty conclusive,” observed Thorndyke, lifting the stopper out of the reagent bottle, “but we will apply the final test.” He dropped a few drops of the hypochlorite solution on to the tile, and immediately the black stain faded away and vanished. “We can now answer your question, Mr. Barton,” said he, replacing the stopper as he turned to our client. “The specimen that you brought us certainly contains arsenic, and in very considerable quantities.”
“Then,” exclaimed Mr. Barton, starting from his chair, “you will come and help me to rescue my brother from this dreadful peril. Don’t refuse me, Dr. Thorndyke, for mercy’s sake, don’t refuse.”
Thorndyke reflected for a moment.
“Before we decide,” said he, “we must see what engagements we have.”
With a quick, significant glance at me, he walked into the office, whither I followed in some bewilderment, for I knew that we had no engagements for the evening.
“Now, Jervis,” said Thorndyke, as he closed the office door, “what are we to do?”
“We must go, I suppose,” I replied. “It seems a pretty urgent case.”
“It does,” he agreed. “Of course, the man may be telling the truth, after all.”
“You don’t think he is, then?”
“No. It is a plausible tale, but there is too much arsenic in that arrowroot. Still, I think I ought to go. It is an ordinary professional risk. But there is no reason why you should put your head into the noose.”
“Thank you,” said I, somewhat huffily. “I don’t see what risk there is, but if any exists I claim the right to share it.”
“Very well,” he answered with a smile, “we will both go. I think we can take care of ourselves.”
He re-entered the sitting-room, and announced his decision to Mr. Barton, whose relief and gratitude