“O’Farrell’s got to clean up.  That’s all there is to that,” he said decisively.

“The Doctor thinks?” queried the little physician.

Dr. Surtaine shook his head.  “I don’t know.  But I’m sure of one thing.  There’s three of them ought to be gotten out at once.  The third-floor woman, and that brother and sister in the basement.”

“And the German family at the top?”

Dr. Surtaine tapped his chest significantly.  “Sure to be plenty of that in this kind of hole.  Nothing to do but let ’em die.”  He did not mention that he had left a twenty-dollar bill and a word of cheer with the gasping consumptive and his wife.  Outside of the line of business Dr. Surtaine’s charities were silent.  “How many of the other cases have you had here?”

“Eleven.  Seven deaths.  Four I take away.”

“And what is your diagnosis, Doctor?” inquired the old quack professionally of the younger ignoramus.

Again De Vito shrugged.  “For public, malignant malaria.  How you call it?  Pernicious.  For me, I do’ know.  Maybe—­” he leaned forward and spoke a low word.

“Meningitis?” repeated the other.  “Possibly.  I’ve never seen much of the infectious kind.  What are you giving for it?”

“Certina, mostly.”

Dr. Surtaine looked at him sharply, but the Italian’s face was innocent of any sardonic expression.

“As well that as anything,” muttered its proprietor.  “By the way, you might get testimonials from any of ’em that get well.  Can you find O’Farrell?”

“Yes, sir.”

“Tell him I want to see him at my office at two o’clock.”

“Ver’ good.  What do you think it is, Doctor?”

Dr. Surtaine waved a profound hand.  “Very obscure.  Demands consideration.  But get those cases out of the city.  There’s no occasion to risk the Board of Health seeing them.”

At the corner Dr. Surtaine again met Miss Elliot and stopped her.  “My dear young lady, ought you to be risking your safety in such places as these?”

“No one ever interferes.  My badge protects me.”

“But there’s so much sickness.”

“That is what brings me,” she smiled.

“It might be contagious.  In fact, I have reason to believe that there is—­er—­measles in this block.”

“I’ve had it, thank you.  May I give you a lift in my car?”

“No, thank you.  But I think you should consult your uncle before coming here again.”

“The entire Surtaine family seems set upon barring me from the Rookeries.  I wonder why.”

With which parting shot she left him.  Going home, he bathed and changed into his customary garb of smooth black, to which his rotund placidity of bearing imparted an indescribably silky finish.  His discarded clothes he put, with his own hands, into an old grip, sprinkled them plenteously with a powerful disinfectant, and left orders that they be destroyed.  It was a phase of Dr. Surtaine’s courage that he never took useless risks, either with his own life, or (outside of business) with the lives of others.