of the height of the column of mercury indicated, I knew, blood
pressure. This time, as he worked, I noted also the flabby skin of
Pitts as well as the small and sluggish pupils of his eyes.

He completed his test in silence and excused himself, although as
we went back to the kitchen I was burning with curiosity.

"What was it?" I asked. "What did you discover?"

"That," he replied, "was a sphygmomanometer, something like the
sphygmograph which we used once in another case. Normal blood
pressure is 125 millimetres. Mr. Pitts shows a high pressure, very
high. The large life insurance companies are now using this
instrument. They would tell you that a high pressure like that
indicates apoplexy. Mr. Pitts, young as he really is, is actually
old. For, you know, the saying is that a man is as old as his
arteries. Pitts has hardening of the arteries, arteriosclerosis--
perhaps other heart and kidney troubles, in short pre-senility."

Craig paused: then added sententiously as if to himself: "You have
heard the latest theories about old age, that it is due to
microbic poisons secreted in the intestines and penetrating the
intestinal walls? Well, in premature senility the symptoms are the
same as in senility, only mental acuteness is not so impaired."

We had now reached the kitchen again. The student had also brought
down to Kennedy a number of sterilised microscope slides and test-
tubes, and from here and there in the masses of blood spots
Kennedy was taking and preserving samples. He also took samples of
the various foods, which he preserved in the sterilised tubes.