“You can’t see them move here, because the air has paralyzed them.  But these vibrios move among the corpuscles of the blood just as a snake moves through the grass, to quote Pasteur.  If I colored them you would see that each is covered with fine vibrating hairs three or four times as long as itself.  At certain times an oval mass forms in them.  That is the spore which lives so long and is so hard to kill.  It was the spores that were on the bullet.  They resist any temperature except comparatively high and prolonged, and even resist antiseptics for a long time.  On the surface of a wound they aren’t so bad; but deep in they distil minute gas bubbles, puff up the surrounding tissues, and are almost impossible to combat.”

As he explained what he had found, I could only stare at him while the diabolical nature of the attack impressed itself on my mind.  Some one had tried to murder Marlowe in this most hideous way.  No need to be an accurate marksman when a mere scratch from such a bullet meant ultimate death anyhow.

Why had it been done and where had the cultures come from?  I asked myself.  I realized fully the difficulty of trying to trace them.  Any one could purchase germs, I knew.  There was no law governing the sale.

Craig was at work again over his microscope.  Again he looked up at me.  “Here on this other film I find the same sort of wisp-like anaerobes,” he announced.  “There was the same thing on those pieces of glass that I got.”

In my horror at the discovery, I had forgotten the broken package that had come to the hotel desk while we stood there.

“Then it was Gavira who was receiving spores and cultures of the anaerobes!” I exclaimed, excitedly.

“But that doesn’t prove that it was he who used them,” cautioned Craig, adding, “not yet, at least.”

Important as the discoveries were which he had made, I was not much farther along in fixing the guilt of anybody in particular in the case.  Kennedy, however, did not seem to be perturbed, though I wondered what theory he could have worked out.

“I think the best thing for us to do will be to run over to the Belleclaire,” he decided as he doffed his laboratory coat and carefully cleansed his hands in an antiseptic almost boiling hot.  “I should like to see Marlowe again, and, besides, there we can watch some of these people around him.”

Whom he meant other than Gavira I had no idea, but I felt sure that with the launching now only a matter of hours something was bound to happen soon.

Marlowe was out when we arrived; in fact, had not yet returned from the yard.  Nor had many of the guests remained at the hotel during the day.  Most of them had been out sightseeing, though now they were returning, and as they began to gather in the hotel parlor Marjorie was again called on to put them at their ease.

Fitzhugh had returned and had wasted no time dressing and getting down-stairs again to be near Marjorie.  Gavira also appeared, having been out on a case.