Instantly Kennedy signaled our driver to stop and together we hopped out and walked back, cautiously entering the vestibule.  The name in the letter-box was “Mrs. Reba Rinehart.”  What could it mean?

Just then another cab stopped up the street, and as we turned to leave the vestibule Kennedy drew back.  It was too late, however, not to be seen.  A man had just alighted and, in turn, had started back, also realizing that it was too late.  It was Chapelle!  There was nothing to do but to make the best of it.

“Shadowing the shadowers?” queried Kennedy, keenly watching the play of his features under the arc-light of the street.

“Miss Cynthia asked me to follow her mother the other night,” he answered, quite frankly.  “And I have been doing so ever since.”

It was a glib answer, at any rate, I thought.

“Then, perhaps you know something of Reba Rinehart, too,” bluffed Kennedy.

Chapelle eyed us a moment, in doubt how much we knew.  Kennedy played a pair of deuces as if they had been four aces instead.

“Not much,” replied Chapelle, dubiously.  “I know that Mrs. Blakeley has been paying money to the old woman, who seems to be ill.  Once I managed to get in to see her.  It’s a bad case of pernicious anemia, I should say.  A neighbor told me she had been to the college hospital, had been one of Doctor Haynes’s cases, but that he had turned her over to his son.  I’ve seen Hampton Haynes here, too.”

There was an air of sincerity about Chapelle’s words.  But, then, I reflected that there had also been a similar ring to what we had heard Hampton say.  Were they playing a game against each other?  Perhaps—­but what was the game?  What did it all mean and why should Mrs. Blakeley pay money to an old woman, a charity patient?

There was no solution.  Both Kennedy and Chapelle, by a sort of tacit consent, dismissed their cabs, and we strolled on over toward Broadway, watching one another, furtively.  We parted finally, and Craig and I went up to our apartment, where he sat for hours in a brown study.  There was plenty to think about even so far in the affair.  He may have sat up all night.  At any rate, he roused me early in the morning.

“Come over to the laboratory,” he said.  “I want to take that X-ray machine up there again to Blakeley’s.  Confound it!  I hope it’s not too late.”

I lost no time in joining him and we were at the house long before any reasonable hour for visitors.

Kennedy asked for Mrs. Blakeley and hurriedly set up the X-ray apparatus.  “I wish you would place that face mask which she was wearing exactly as it was before she became ill,” he asked.

Her mother did as Kennedy directed, replacing the rubber mask as Virginia had worn it.

“I want you to preserve that mask,” directed Kennedy, as he finished taking his pictures.  “Say nothing about it to any one.  In fact, I should advise putting it in your family safe for the present.”