Kennedy had risen to go.  “You have had no word about your car?” he asked casually.

“None yet.  I’m not worrying.  It was insured.”

“Who is this arch criminal, Dr. Hopf?” I mused as we retraced our steps to the laboratory.  “Is Mrs. Blake stricken now by the same trouble that seems to have affected Buster?”

“Only my examination will show,” he said.  “I shall let nothing interfere with that now.  It must be the starting point for any work that I may do in the case.”

We arrived at Kennedy’s workshop of scientific crime and he immediately plunged into work.  Looking up he caught sight of me standing helplessly idle.

“Walter,” he remarked thoughtfully adjusting a microscope, “suppose you run down and see Garwood.  Perhaps he has something to report.  And by the way, while you are out, make inquiries about the Blakes, young Baldwin, Miss Sears and this Dr. Wilson.  I have heard of her before, at least by name.  Perhaps you may find something interesting.”

Glad to have a chance to seem to be doing something whether it amounted to anything or not, I dropped in to see Garwood.  So far he had nothing to report except the usual number of false alarms.  From his office I went up to the Star where fortunately I found one of the reporters who wrote society notes.

The Blakes, I found, as we already knew, to be well known and moving in the highest social circles.  As far as known they had no particular enemies, other than those common to all people of great wealth.  Dr. Wilson had a large practice, built up in recent years, and was one of the best known society physicians for women.  Miss Sears was unknown, as far as I could determine.  As for Duncan Baldwin, I found that he had become acquainted with Reginald Blake in college, that he came of no particular family and seemed to have no great means, although he was very popular in the best circles.  In fact he had had, thanks to his friend, a rather meteoric rise in society, though it was reported that he was somewhat involved in debt as a result.

I returned to the laboratory to find that Craig had taken out of a cabinet a peculiar looking arrangement.  It consisted of thirty-two tubes, each about sixteen inches long, with S-turns, like a minute radiator.  It was altogether not over a cubic foot in size, and enclosed in a glass cylinder.  There were in it, perhaps, fifty feet of tubes, a perfectly-closed tubular system which I noticed Kennedy was keeping absolutely sterile in a germicidal solution of some kind.

Inside the tubes and surrounding them was a saline solution which was kept at a uniform temperature by a special heating apparatus.

Kennedy had placed the apparatus on the laboratory table and then gently took the little dog from his basket and laid him beside it.  A few minutes later the poor little suffering Buster was mercifully under the influence of an anesthetic.

Quickly Craig worked.  First he attached the end of one of the tubes by means of a little cannula to the carotid artery of the dog.  Then the other was attached to the jugular vein.