anybody else going on with it, I wondered; and if so, with what success?

You see, the world was dead to me. No news of it filtered in. The
history of science was making fast, and I was interested in a thousand
subjects. Why, there was my theory of the hydrolysis of casein by
trypsin, which Professor Walters had been carrying out in his laboratory.
Also, Professor Schleimer had similarly been collaborating with me in the
detection of phytosterol in mixtures of animal and vegetable fats. The
work surely was going on, but with what results? The very thought of all
this activity just beyond the prison walls and in which I could take no
part, of which I was never even to hear, was maddening. And in the
meantime I lay there on my cell floor and played games with house-flies.

And yet all was not silence in solitary. Early in my confinement I used
to hear, at irregular intervals, faint, low tappings. From farther away
I also heard fainter and lower tappings. Continually these tappings were
interrupted by the snarling of the guard. On occasion, when the tapping
went on too persistently, extra guards were summoned, and I knew by the
sounds that men were being strait-jacketed.

The matter was easy of explanation. I had known, as every prisoner in
San Quentin knew, that the two men in solitary were Ed Morrell and Jake
Oppenheimer. And I knew that these were the two men who tapped knuckle-
talk to each other and were punished for so doing.

That the code they used was simple I had not the slightest doubt, yet I
devoted many hours to a vain effort to work it out. Heaven knows--it had
to be simple, yet I could not make head nor tail of it. And simple it
proved to be, when I learned it; and simplest of all proved the trick
they employed which had so baffled me. Not only each day did they change