Phil Courtney got to his feet. "Strychnine—" he began.
Taking a somewhat crumpled cigar from his pocket, H.M. bit off the end, expectorated the end neatly across into the fireplace, and lit the cigar. Its smoke hung round his head in an oily cloud.
"The point is," he explained, "that the symptoms of tetanus are exactly the same as the symptoms of strychnine poisoning, except that the effects of strychnine come on a whole lot quicker. The only slight difference is in the nature of the cramps — the muscles are in a continuous state o' contraction for tetanus" — but nothing that would bother the keenest doctor if he'd already got tetanus in his mind."
H.M. blew out smoke somberly.
"It wasn't us that saved Mrs. Fane's life, son," he added. "It was only the fact that the murderer gave her too big a dose. It was so whackin' big that it neutralized itself. Once I sent for a stomach-pump…"
Courtney, without seeing him, stared at the past. It was as though many blurred pictures had now come into focus to form a series-
"Nice pleasant gentleman or lady, this murderer," observed Masters grimly. "Oh, ah! You've got a bit of a better idea now, haven't you, Mr. Courtney?" Courtney had.
"Just a minute!" he begged. "When was the strychnine given to her, then?"
"About four o'clock on Thursday afternoon, we make it," replied Masters. "That's to say: about twenty minutes before the symptoms started to come on. Strychnine usually begins to work within twenty minutes."
"I see. And it was administered through the mouth, wasn't it? In a grapefruit?" H.M. raised his eyebrows.