"And is that all that could be learned?" I asked.
"No," he continued. "Further development may enable men to picture the figures engraved on the convolutions, and at last to read the thoughts that are engraved within the brains of others, and thus through material investigation the observer will perceive the recorded thought of another person. An instrument capable of searching and illuminating the retina could be easily affixed to the eye of a criminal, after which, if the mind of the person operated upon were stimulated by the suggestion of an occurrence either remote or recent, the mind facility would excite the brain, produce the record, and spread the circumstances as a picture before the observer. The brain would tell its own story, and the investigator could read the truth as recorded in the brain of the other man. A criminal subjected to such an examination could not tell an untruth, or equivocate; his very brain would present itself to the observer."
"And you make this assertion, and then ask me to go no further into the subject?"
"Yes; decidedly yes."
"Tell me, then, could you not have performed this experiment in my room, or in the dark cellar of my house?"
"Any one can repeat it with a candle in any room not otherwise lighted, by looking at a blackboard, a blank wall, or black space," he said.
I was indignant.
"Why have you treated me so inhumanly? Was there a necessity for this journey, these mysterious movements, this physical exertion? Look at the mud with which I am covered, and consider the return trip which yet lies before me, and which must prove even more exhausting?"
"Ah," he said, "you overdraw. The lesson has been easily acquired. Science is not an easy road to travel. Those who propose to profit thereby must work circuitously, soil their hands and person, meet discouragements, and must expect hardships, reverses, abuse, and discomfort. Do not complain, but thank me for giving you the lesson without other tribulations that might have accompanied it. Besides, there was another object in my journey, an object that I have quietly accomplished, and which you may never know. Come, we must return."
He extinguished the light of the candle, and we departed together, trudging back through the mud and the night.[8]