“However, everything points to the conclusion now that it was snake venom, and my physiological tests on the guinea pig seem to confirm it.  I see no reason now to doubt that it was snake venom.  The fact of the matter is that the snake venoms are about the safest of poisons for the criminal to use, for the reason of the difficulty they give in any chemical analysis.  That is only another proof of the diabolical cleverness of our guilty person, whoever it may be.

“Later I’ll identify the particular kind of venom used.  Just now I feel it is more important to discover the actual motive for the crime.  In the morning I have a plan which may save me further work here in the laboratory, but for to-night I feel I have earned a rest and”—­a smile—­“I shall rest by searching out the motives of these temperamental movie folk a little more.”  As he spoke he slipped out of his acid-stained smock.

“What do you mean?” As often, he rather baffled me.

“It’s nearly dinner time and we’re going out together, Walter, down to Jacques’.”

“Why Jacques’?”

“Because I phoned your friend Belle Balcom and she informed me that that was the place where we would be apt to find the elite of the film world dining.”

I acquiesced, of course.  We hurried to the apartment first for a few necessary changes and preparations, then we started for the Times Square section in a taxi.

“I never heard of the use of snake venom before,” I remarked, settling back in the cushions—­“that is, deliberately, by a criminal, to poison anyone.”

“There are cases,” replied Craig, absently.

“Just how does the venom act?”

“I believe it is generally accepted that there are two agents present in the secretion.  One is a peptone and the other a globulin.  One is neurotoxic, the other hemolytic.  Not only is the general nervous system attacked instantly, but the coagulability of the blood is destroyed.  One agent in the venom attacks the nerve cells; the other destroys the red corpuscles.”

“You suspected something of this kind, then, when you first examined Stella Lamar?”

“Exactly!  You see, the victim of a snake bite often is unable to move or speak.  Doctor Blake observed that in the case of the stricken star.  Her nerves were affected, resulting in paralysis of the muscles of the heart and lungs and giving us some symptoms of suffocation.  Then the blood, as a result of the attack of the venom, is always left dark and liquid.  That, too, I observed in the sample sent me from Tarrytown.

“The snake,” Kennedy continued, “administers the poison by fangs more delicate than any hypodermic.  Nature’s apparatus is more precise than the finest appliances devised for the use of a surgeon by our instrument makers.  The fangs are like needles with obliquely cut points and slit-like outlets.  The poison glands correspond to the bulb of a syringe.  They are, in reality, highly modified salivary glands.  From them, when the serpent strikes, is ejected a pale straw-colored half-oleaginous fluid.  You might swallow it with impunity.  But once in the blood, through a cut or wound, it is deadly.”