The look of distress had vanished, and his sincere eyes seemed to shine
again with courage and with strength.

"Good-bye."

When he was gone, Isaacson stood by the mantel-piece for nearly five
minutes, thinking and motionless. The sound of the little clock striking
roused him. He lifted his head, looked around him, and was just going to
switch off the light, when he noticed the open book on his table. He
went to shut it up.

"It must be ever remembered that digitalin is a cumulative poison, and
that the same dose, harmless if taken once, yet frequently repeated
becomes deadly; this peculiarity is shared by all poisons affecting the
heart."

He stood looking at the page.

"This peculiarity is shared by all poisons affecting the heart."

He moved his head as if in assent. Then he closed the book slowly and
switched off the light.

On the August Bank Holiday, one of the most dreadful days of London's
year, he set out to call on Mrs. Chepstow.

A stagnant heat pervaded London. There were but few people walking. Few
vehicles drove by. Here and there small groups of persons, oddly
dressed, and looking vacant in their rapture, stared, round-eyed, on the