Kennedy was now looking closely at the handkerchief, and I looked also.  In the glasses had been innumerable little seeds as if from the fruit juice used in concocting the appetizer.  The fine meshes of the linen had extracted them.  What were they?

I took one in my fingers and crushed it between my nails.  There was an unmistakable odor of bitter almonds.  What did it mean?

We had no time now for speculation.  Our prolonged absence might be noticed and we hastened to join the other guests after finishing the round of glasses in which he had been interrupted.

How, in my suppressed excitement, I managed to get through that dinner I do not know.  It was a brilliant affair, yet I found that I had completely lost my appetite, as well one might after having observed Kennedy’s sleuthing.

However, the dinner progressed, though each course that brought it nearer a conclusion afforded me an air of relief.  I was quite ready when, over the coffee, Kennedy contrived to make some excuse for us, promising to call again and perhaps to visit the Erickson plantation.

In the secrecy of our room in the little hotel, Craig was soon deeply buried in making use of his traveling laboratory.  As he worked I could no longer restrain my impatience.  “What about that little bottle of keratin?” I asked, eagerly.

“Oh yes,” he replied, not looking up from the tests he was making.  “Well, keratin, you know, is also called epidermose.  It is a scleroprotein present largely in cuticular structures such as hair, nails, horn.  I believe it is usually prepared from pieces of horn steeped in pepsin, hydrochloric acid, and water for a long time.  Then the residue is dissolved in ammonia and acetic acid.”

“But what’s its use?” I demanded.  “You said it was harmless.”

“Why, the pepsin of the stomach won’t digest it,” he returned.  “For that reason its chief use is for coating what are known as ‘enteric capsules.’  Anything coated with keratin is carried on through the stomach into the intestines.  It is used much in hot countries in order to introduce drugs into the intestines in the treatment of the tropical diseases that affect the intestines.”  He paused and devoted his entire attention to his work, but he had told me enough to assure me that at least the bottle of keratin I had found had proved to be a clue.

I waited as long as I could, then interrupted again.  “What are the seeds?” I queried.  “Have you found out yet?”

He paused as though he had not quite finished his hasty investigation, yet had found out enough to convince him.  “There seem to be two kinds.  I wish I had had time to keep each lot separate.  Some of them are certainly quite harmless.  But there are others, I find, that have been soaked in nitro-benzol, artificial oil of bitter almonds.  Even a few drops, such as might be soaked up in this way, might be fatal.  The new and interesting phase, to me, is that they were all carefully coated with keratin.  Really, they are keratin-coated enteric capsules of nitro-benzol, a deadly poison.”