He had already placed it in a porcelain basin, and in this basin
he had poured some liquids. Then he passed the liquids through a
fine screen and at last took up a tube containing some of the
resulting liquid.
"I have already satisfied myself," he explained, "but for your
benefit, seeing that you're the chief sufferer, I'll run over a
part of the test. You saw the reaction which showed the gas a
moment ago. I have proved chemically as well as microscopically
that it is present in your blood. Now if I take this test-tube of
liquid derived from my treatment of the lock and then test it as
you saw me do with the other, isn't that enough for you? See--it
gives the same reaction."
It did, indeed, but my mind did not react with it.
"Nitrous oxide," he continued, "in contact with iron, leaves
distinct traces of corrosion, discernible by chemical and
microscopic tests quite as well as the marks it leaves in the
human blood. Manifestly, if no one could have come in by the
windows or doors, the gas must have been administered in some way
without any one coming into the room. I found no traces of an
intruder."
It was a tough one. Never much good at answering his conundrums
when I was well, I could not even make a guess now.
Pages:
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247