“Professor,” asked Watson, “is it the occult?”

“Ah,” brightening; “now we are getting back to the old point.  However, what is the occult?” He paused; then—­“Did it ever occur to you, that the occult might prove to be the real world, proving that life we have known to be merely a shadow?”

Silence greeted this.  The professor went on: 

“Let me ask you:  Are you living in a real world now, or an unreal one?” There was no response.  “It is, of course, a reality; just as truly as if you were in San Francisco.  So,” very distinctly, “perhaps it is merely a question of viewpoint, as to which is the occult!”

“Just what we want to know,” from Harry.

“And that,” tossing up his hands, “is exactly what I cannot tell you.  I have found out many things, but I cannot be sure.  I left certainty in Berkeley.

“Today I feel that there is some great fate, some unknown force that defies analysis, defies all attempts at resolution—­a force that is driving me through the role of the Jarados.  We are all a part of the Prophecy!

“We must wait for the last day for our answer.  That Prophecy must and will be fulfilled.  And on that day we shall have the key to the Blind Spot—­we shall know the where of the occult.”

He took a sip from a tumbler of the familiar green fluid.

“Now that I have told you this much, I am going back to the beginning.  I, too, have had adventures.

“How did I come to discover the Blind Spot?

“It was about one year prior to my last lecture at the university.  At the time I had been doing much psychic-research work, all of which you know.  And out of it I had adduced some peculiar theories.  For example: 

“Undoubtedly there is such a thing as a spirit world.  If all the mediums but one were dishonest, and that one produced the results that couldn’t be explained away by psychology, then we must admit the existence of another world.

“But reason tells us that there is nothing but reality; that if there were a spirit world it must be just as real, just as substantial as our own.  Moreover—­somewhere, somehow, here must be a definite point of contact!

“That was approximately my theory.  Of course I had no idea how close I had come to a great truth.  To some extent it was pure guesswork.

“Then, one day Budge Kennedy brought me the blue stone.  He told me its history, and he maintained that it was lighter than air, which of course I disbelieved until I took it out of the ring and saw for myself.

“I went at once to the house at 288 Chatterton Place.  There I found an old lady who had lived in the house for some time.  I asked to see the cellar where the stone had been unearthed.  Understand, I had no idea of the great discovery I was about to make; I merely wanted to see.  And I found something almost as impossible as the blue stone itself-a green one, heavier than any known mineral, answering to no known classification but of an entirely new element.  It was no larger than a pea, but of incredible weight.