Drumm pondered the point.
"Roughly, let us say, at two this morning."
"And the strychnine might have been taken as early as eleven or twelve?"
"It's possible."
"Anyhow, we'll know about it when Doc Doremus gets here," asserted Heath with brutal frankness. He was in vicious mood that morning.
"Did you find any glass or cup by which the drug might have been administered, doctor?" Markham hastened to ask, by way of covering up Heath's remark.
"There was a glass near the bed with what appeared to be sulphate crystals adhering to the sides of it."
"But wouldn't a fatal dose of strychnine make an ordin'ry drink noticeably bitter?" Vance had suddenly become alert.
"Undoubtedly. But there was a bottle of citrocarbonate—a well-known antacid—on the night-table; and if the drug had been taken with this, the taste would not have been detected. Citrocarbonate is slightly saline and highly effervescing."
"Could Mrs. Greene have taken the citrocarbonate alone?"
"It's not likely. It has to be carefully mixed with water, and the operation would be highly awkward for any one in bed."
"Now, that's most interestin'." Vance listlessly lighted a cigarette. "We may presume, therefore, that the person who gave Mrs. Greene the citrocarbonate also administered the strychnine." He turned to Markham. "I think Miss O'Brien might be able to help us."
