“The writer of that letter,” he went on, waving the piece of sterile platinum wire with which he had been transferring drops of liquid in his search for germs, “was a much more skillful bacteriologist than I thought, evidently. No, the trouble does not seem to be from germs breathed in, or from germs at all—it is from some kind of germ-free toxin that has been injected or otherwise introduced.”
Vaguely now I began to appreciate the terrible significance of what he had discovered.
“But the letter?” I persisted mechanically.
“The writer of that was quite as shrewd a psychologist as bacteriologist,” pursued Craig impressively. “He calculated the moral effect of the letter, then of Buster’s illness, and finally of reaching Mrs. Blake herself.”
“You think Dr. Rae Wilson knows nothing of it yet?” I queried.
Kennedy appeared to consider his answer carefully. Then he said slowly: “Almost any doctor with a microscope and the faintest trace of a scientific education could recognize disease germs either naturally or feloniously implanted. But when it comes to the detection of concentrated, filtered, germ-free toxins, almost any scientist might be baffled. Walter,” he concluded, “this is not mere blackmail, although perhaps the visit of that woman to the Prince Henry—a desperate thing in itself, although she did get away by her quick thinking—perhaps that shows that these people are ready to stop at nothing. No, it goes deeper than blackmail.”
I stood aghast at the discovery of this new method of scientific murder. The astute criminal, whoever he might be, had planned to leave not even the slender clue that might be afforded by disease germs. He was operating, not with disease itself, but with something showing the ultimate effects, perhaps, of disease with none of the preliminary symptoms, baffling even to the best of physicians.
I scarcely knew what to say. Before I realized it, however, Craig was at last ready for the promised visit to Mrs. Blake. We went together, carrying Buster, in his basket, not recovered, to be sure, but a very different little animal from the dying creature that had been sent to us at the laboratory.
CHAPTER XXI
THE POISON BRACELET
We reached the Blake mansion and were promptly admitted. Miss Betty, bearing up bravely under Reginald’s reassurances, greeted us before we were fairly inside the door, though she and her brother were not able to conceal the fact that their mother was no better. Miss Sears was out, for an airing, and the new nurse, Miss Rogers, was in charge of the patient.