key but couldn't find the keyhole. I have found that concentration upon microscopic work often permits

me to think more freely upon problems. So I took a few smears of Peters' blood and began to study

them, not with any expectation of finding anything, but to slip the brakes from another part of my brain.

I was on my fourth slide when I suddenly realized that I was looking at the incredible. As I had

perfunctorily moved the slide, a white corpuscle had slid into the field of vision. Only a simple white

corpuscle-but within it was a spark of phosphorescence, shining out like a tiny lamp!

I thought at first that it was some effect of the light, but no manipulation of the illumination changed that

spark. I rubbed my eyes and looked again. I called Hoskins.

"Tell me if you see something peculiar in there."

He peered into the microscope. He started, then shifted the light as I had.