death swift and terrible, death full of pain and indignity—­would be released upon this city, and go hither and thither seeking his victims.  Here he would take the husband from the wife, here the child from its mother, here the statesman from his duty, and here the toiler from his trouble.  He would follow the water-mains, creeping along streets, picking out and punishing a house here and a house there where they did not boil their drinking-water, creeping into the wells of the mineral-water makers, getting washed into salad, and lying dormant in ices.  He would wait ready to be drunk in the horse-troughs, and by unwary children in the public fountains.  He would soak into the soil, to reappear in springs and wells at a thousand unexpected places.  Once start him at the water supply, and before we could ring him in, and catch him again, he would have decimated the metropolis.”

He stopped abruptly.  He had been told rhetoric was his weakness.

“But he is quite safe here, you know—­quite safe.”

The pale-faced man nodded.  His eyes shone.  He cleared his throat.  “These Anarchist—­rascals,” said he, “are fools, blind fools—­to use bombs when this kind of thing is attainable.  I think—­”

A gentle rap, a mere light touch of the finger-nails was heard at the door.  The Bacteriologist opened it.  “Just a minute, dear,” whispered his wife.

When he re-entered the laboratory his visitor was looking at his watch.  “I had no idea I had wasted an hour of your time,” he said.  “Twelve minutes to four.  I ought to have left here by half-past three.  But your things were really too interesting.  No, positively I cannot stop a moment longer.  I have an engagement at four.”

He passed out of the room reiterating his thanks, and the Bacteriologist accompanied him to the door, and then returned thoughtfully along the passage to his laboratory.  He was musing on the ethnology of his visitor.  Certainly the man was not a Teutonic type nor a common Latin one.  “A morbid product, anyhow, I am afraid,” said the Bacteriologist to himself.  “How he gloated on those cultivations of disease-germs!” A disturbing thought struck him.  He turned to the bench by the vapour-bath, and then very quickly to his writing-table.  Then he felt hastily in his pockets, and then rushed to the door.  “I may have put it down on the hall table,” he said.

“Minnie!” he shouted hoarsely in the hall.

“Yes, dear,” came a remote voice.

“Had I anything in my hand when I spoke to you, dear, just now?”

Pause.

“Nothing, dear, because I remember—­”

“Blue ruin!” cried the Bacteriologist, and incontinently ran to the front door and down the steps of his house to the street.