together they had come to the conclusion that death was
due to the action of prussic acid, which had caused instantaneous
failure of the heart, but how the drug had been administered neither he
nor his colleague were at present able to state.

"'Do I understand, then, Dr. Jones, that the deceased died, poisoned
with prussic acid?'

"'Such is my opinion,' replied the doctor.

"'Did the bottle found in her satchel contain prussic acid?'

"'It had contained some at one time, certainly.'

"'In your opinion, then, the lady caused her own death by taking a dose
of that drug?'

"'Pardon me, I never suggested such a thing; the lady died poisoned by
the drug, but how the drug was administered we cannot say. By injection
of some sort, certainly. The drug certainly was not swallowed; there was
not a vestige of it in the stomach.'

"'Yes,' added the doctor in reply to another question from the coroner,
'death had probably followed the injection in this case almost
immediately; say within a couple of minutes, or perhaps three. It was
quite possible that the body would not have more than one quick and
sudden convulsion, perhaps not that; death in such cases is absolutely
sudden and crushing.'

"I don't think that at the time any one in the room realized how
important the doctor's statement was, a statement which, by the way, was
confirmed in all its details by the district medical officer, who had
conducted the postmortem. Mrs. Hazeldene had died suddenly from an
injection of prussic acid, administered no one knew how or when. She
had been travelling in a first-class railway carriage in a busy time of
the day. That young and elegant woman must have had singular nerve and
coolness to go through the process of a self-inflicted injection of a
deadly poison in the presence of perhaps two or three other persons.

"Mind you, when I say that no one there realized the importance of the
doctor's statement at that moment, I am wrong; there were three persons,
who fully understood at once the gravity of the situation, and the
astounding development which the case was beginning to assume.

"Of course, I should have put myself out of the question," added the
weird old man, with that inimitable self-conceit peculiar to himself. "I
guessed then and there in a moment where the police were going wrong,
and where they would go on going wrong until the mysterious death on the
Underground Railway had sunk into oblivion, together with the oth