"Then the case was unguarded in the rear of the upper hall from about eleven until you left the house?"
"Yes. After I had taken leave of you gentlemen in the drawing-room I went up-stairs and got it."
"And also made your adieus to Miss Sibella," added Vance.
Von Blon raised his eyebrows with an air of gentle surprise.
"Naturally."
"What amount of these drugs disappeared?" asked Markham.
"The four tubes of strychnine contained in all approximately three grains—three and one-third, to be exact. And there are twenty-five tablets of morphine in a Parke-Davis tube, making six and one-quarter grains."
"Are those fatal doses, doctor?"
"That's a difficult question to answer, sir." Von Blon adopted a professorial manner. "One may have a tolerance for morphine and be capable of assimilating astonishingly large doses. But, ceteris paribus, six grains would certainly prove fatal. Regarding strychnine, toxicology gives us a very wide range as to lethal dosage, depending on the condition and age of the patient. The average fatal dose for an adult is, I should say, two grains, though death has resulted from administrations of one grain, or even less. And, on the other hand, recovery has taken place after as much as ten grains have been swallowed. Generally speaking, however, three and one-third grains would be sufficient to produce fatal results."
