The red placards began to disappear; many of them, alas! only after the sable symbol of death had appeared beneath them. Dr. Strong and his worn-out aides found time to draw breath and reckon up their accounts in human life. The early mortality had been terrific. Of the cases which had developed in the period of suppression, before antitoxin was readily obtainable, more than a third had died.

“Nobody will ever be indicted for those murders,” said Dr. Strong to Mr. Clyde grimly. “But we have the satisfaction of knowing what can really be done by prompt work. Look at the figures after the free anti-toxin was established.”

There was a drop in the death rate, first to twenty per cent, then to ten, and, in the ebb stage of the scourge, to well below five.

“How many infections we’ve prevented by giving anti-toxin to immunize exposed persons, there’s no telling,” continued Dr. Strong. “That principle of starting a back-fire in diphtheria,—it’s exactly like starting a back-fire in a prairie conflagration,—by getting anti-toxin into the system in time to head off the poison of the disease itself, is one of the two or three great achievements of medical science. There isn’t an infected household in the city today, I believe, where this hasn’t been done. The end is in sight.”

“Then you can go away and get a few days’ rest,” said Grandma Sharpless, who constituted herself the Health Master’s own health guardian and undiplomaed medical adviser, and to whom he habitually rendered meek obedience; for she had been watching with anxiety the haggard lines in his face.

“Not yet,” he returned. “Measles we still have with us.”

“Decreasing, though,” said Mrs. Clyde. “Our nurses report a heavy drop in new cases and a big crop of convalescents.”

“It is those convalescents that we must watch. I don’t want a generation of deaf citizens growing up from this onset.”

“But can you prevent it if the disease attacks the ears?” asked Clyde.

“Almost certainly. We’ve got to inspect every child who has or had measles in this epidemic, and, where the ear-drum is shiny and concave, we will puncture it, by a very simple operation, which saves serious trouble in ninety per cent of the cases, at least. But it means constant watchfulness, for often the infection progresses without pain.”