im, as Madame Medjora's
was to her? Then why should not she lose her life in payment for the
crime which she had committed, her victim being a defenceless and
confiding dog? Leon pictured to himself how she had accomplished the
deed. He saw, in his mind, the poor creature going to her, and thus
placing himself within her power. The thought maddened him, and
setting his teeth together he muttered audibly:

"She shall die!"

Then his brain sought some way to compass such an end with safety to
himself, and before long he had concocted a scheme of devilish
ingenuity. His knowledge of chemistry warned him that poisons could be
traced in the tissues of the body after death, and that such means
would be suicidal.

"But suppose she were to die a natural death? Then, not even suspicion
would be aroused."

That was the idea. He must convey to her the germs of some deadly
disease from which she would be apt to die. Then the _post-mortem_
would show nothing out of the common. There would be no way to detect
how the disease had been contracted. The attending physician would
certify that the death was due to a known disease, and an autopsy, if
held, would substantiate his statements.

What disease should he choose? Asiatic cholera? He had some pure
cultures in a tube in the laboratory. But no! That would not serve his
purpose. Cholera is such an uncommon and dangerous malady, that the
Board of Health would strictly investigate a sporadic case. It might
not be difficult to trace the fact that he had obtained the germs from
the European laboratory whence they had been sent to Dr. Medjora for
experimental purposes. It would be safer to select some disease of
frequent occurrence. He had the germs of diphtheria also, in the form
of a pure culture. Should he use them? It would not be sure that the
woman would die, but at any rate she might, and surely she would
suffer. Yes! He would cause her to contract diphtheria. But how to
proceed? Ah! He would use chloroform upon her in her natural sleep,
and thus obtain the opportunity for his inoculation.

And so the idea grew, and his plans were arranged and perfected hour
after hour, until at last midnight had arrived. Stealthily he left his
room and went towards the Doctor's study. Arrived there, he was about
to cross and enter the laboratory, when his attention was attracted by
a line of light under the door. Some one was evidently in the
laboratory. Leon slipped behind a curtain and wai