"About midnight I suddenly awoke with a curious feeling that something was standing beside me. I raised myself in bed, lit a candle, and this is what I saw. In the middle of the room stood an immense cat gazing upon me with phosphorescent eyes, and with its back slightly arched. It was a magnificent Angora, with long fur and a fluffy tail, and of a remarkable color--exactly like that of the yellow silk that one sees in cocoons--so that, as the light gleamed upon its coat, the animal seemed to be made of gold. "It slowly moved toward me on its velvety paws, softly rubbing its sinuous body against my legs. I leaned over to stroke it, and it permitted my caress, purring, and finally leaping upon my knees. I noticed then that it was a female cat, quite young, and that she seemed disposed to permit me to pet her as long as ever I would. Finally, however, I put her down upon the floor, and tried to induce her to leave the room; but she leaped away from me and hid herself somewhere among the furniture, though as soon as I had blown out my candle, she jumped upon my bed. Being sleepy, however, I didn't molest her, but dropped off into a doze, and the next morning when I awoke in broad daylight I could find no sign of the animal at all. "Truly, the human brain is a very delicate instrument, and one that is easily thrown out of gear. Before I proceed, just sum up for yourselves the facts that I have mentioned: a light seen and presently extinguished in an apartment supposed to be uninhabited; and a cat of a remarkable color, which appeared and disappeared in a way that was slightly mysterious. Now there isn't anything very strange about that, is there? Very well. Imagine, now, that these unimportant facts are repeated day after day and under the same conditions throughout a whole week, and then, believe me, they become of importance enough to impress the mind of a man who is living all alone, and to produce in him a slight disquietude such as I spoke of in commencing my story, and such as is always caused when one approaches the sphere of the unknown. The human mind is so formed that it always unconsciously applies the principle of the causa sufficiens. For every series of facts that are identical, it demands a cause, a law; and a vague dismay seizes upon it when it is unable to guess this cause and to trace out this law. "I am no coward, but I have often studied the manifestation of fear in others, from its most puerile form in children up to its most tragic phase in madmen. I know that it is fed and nourished by uncertainties, although when one actually sets himself to investigate the cause, this fear is often transformed into simple curiosity.