“I may keep these?” he asked.

“Certainly,” replied Mrs. Sutphen.  “That’s what I had Miss McCann get them for.”

Kennedy dropped the bottle into his pocket.

“So that was the gang leader, ‘Whitecap,’” he remarked as we turned again to Broadway.

“Yes,” replied Mrs. Sutphen.  “At certain hours, I believe he can be found at that cabaret selling this stuff, whatever it is, to anyone who comes properly introduced.  The thing seems to be so open and notorious that it amounts to a scandal.”

We parted a moment later, Mrs. Sutphen and Miss McCann to go to the settlement house, Craig and I to continue our investigations.

“First of all, Walter,” he said as we swung aboard an uptown car, “I want to stop at the laboratory.”

In his den, which had been the scene of so many triumphs, Kennedy began a hasty examination of the tablets, powdering one and testing it with one chemical after another.

“What are they?” I asked at length when he seemed to have found the right reaction which gave him the clue.

“Happy dust,” he answered briefly.

“Happy dust?” I repeated, looking at him a moment in doubt as to whether he was joking or serious.  “What is that?”

“The Tenderloin name for heroin—­a comparatively new derivative of morphine.  It is really morphine treated with acetic acid which renders it more powerful than morphine alone.”

“How do they take them?  What’s the effect?” I asked.

“The person who uses heroin usually powders the tablets and snuffs the powder up the nose,” he answered.  “In a short time, perhaps only two or three weeks, one can become a confirmed victim of ‘happy dust.’  And while one is under its influence he is morally, physically and mentally irresponsible.”

Kennedy was putting away the paraphernalia he had used, meanwhile talking about the drug.  “One of the worst aspects of it, too,” he continued, “is the desire of the user to share his experience with some one else.  This passing on of the habit, which seems to be one of the strongest desires of the drug fiend, makes him even more dangerous to society than he would otherwise be.  It makes it harder for anyone once addicted to a drug to shake it off, for his friends will give him no chance.  The only thing to do is to get the victim out of his environment and into an entirely new scene.”

The laboratory table cleared again, Kennedy had dropped into a deep study.

“Now, why was Mrs. Sutphen there?” he asked aloud.  “I can’t think it was solely through her interest for that girl they call Snowbird.  She was interested in her, but she made no attempt to interfere or to follow her.  No, there must have been another reason.”

“You don’t think she’s a dope fiend herself, do you?” I asked hurriedly.

Kennedy smiled.  “Hardly, Walter.  If she has any obsession on the subject, it is more likely to lead her to actual fanaticism against all stimulants and narcotics and everything connected with them.  No, you might possibly persuade me that two and two equal five—­but not seventeen.  It’s not very late.  I think we might make another visit to that cabaret and see whether the same thing is going on yet.”