“He had brass tags on the necks of the rats, and he got back a few—the uninfected ones. The other ones were probably dead. But he couldn’t stop at that. He had to be sure that the trouble had not spread. And to add to their horror the sewer along the street was being relaid, and they had an influx of rats into the house. They found them everywhere in the lower floor. They even climbed the stairs. He says that the night you came he caught a big fellow on the front staircase. There was always the danger that the fleas that carry the trouble had deserted the dead creatures for new fields. They took up all the rest of the carpets and burned them. To add to the general misery the dog Chang developed unmistakable symptoms and had to be killed.”

“But the broken staircase?” I asked. “And what was it that Mademoiselle said was coming up?”

“The steps were up for two reasons: The rats could not climb up, and beneath the steps Reed says he caught in a trap two of the tagged ones. As for Mademoiselle the thing that was coming up was her temperature—pure fright. The head you saw was poor Reed himself, wrapped in gauze against trouble and baiting his traps. He caught a lot in the neighbors’ cellars and some in the garden.”

“But why,” I demanded, “why didn’t he make it all known?”

Mr. Patton laughed while he shrugged his shoulders.

“A man hardly cares to announce that he has menaced the health of a city.”

“But that night when I fell—was it only last night?—someone was pounding above. I thought there was a fire.”

“The Frenchwoman had seen us waylay Reed from her window. She was crazy.”

“And the trouble is over now?”

“Not at all,” he replied cheerfully. “The trouble may be only beginning. We’re keeping Reed’s name out, but the Board of Health has issued a general warning. Personally I think his six pets died without passing anything along.”

“But there was a big box with a lid—”

“Ferrets,” he assured me. “Nice white ferrets with pink eyes and a taste for rats.” He held out a thumb, carefully bandaged. “Reed had a couple under his coat when we took him in the garden. Probably one ran over your foot that night when you surprised him on the back staircase.”

I went pale. “But if they are infected!” I cried; “and you are bitten—”

“The first thing a nurse should learn,” he bent forward smiling, “is not to alarm her patient.”

“But you don’t understand the danger,” I said despairingly. “Oh, if only men had a little bit of sense!”

“I must do something desperate then? Have the thumb cut off, perhaps?”