"Who?" I queried.

"Dr. Leslie," he answered. "He has the authority to compel the
attendance of Mrs. Maitland, Dr. Ross, and Masterson."

The quickness with which he had worked out a case which was, to
me, one of the most inexplicable he had had for a long time, left
me standing speechless.

One by one they dropped in during the next half-hour, and, as
usual, it fell to me to receive them and smooth over the rough
edges which always obtruded at these little enforced parties in
the laboratory.

Dr. Leslie and Dr. Ross were the first to arrive. They had not
come together, but had met at the door. I fancied I saw a touch of
professional jealousy in their manner, at least on the part of Dr.
Ross. Masterson came, as usual ignoring the seriousness of the
matter and accusing us all of conspiring to keep him from the
first night of a light opera which was opening. Mrs. Maitland
followed, the unaccustomed pallor of her face heightened by the
plain black dress. I felt most uncomfortable, as indeed I think
the rest did. She merely inclined her head to Masterson, seemed
almost to avoid the eye of Dr. Ross, glared at Dr. Leslie, and
absolutely ignored me.

Craig had been standing aloof at his laboratory table, beyond a
nod of recognition paying little attention to anything. He seemed
to be in no hurry to begin.