"However, my object in writing this letter is not to point out difficulties of this character, which are probably well understood by the majority of the readers of the _Journal_. It is to draw attention to another fact, and an analogy. Let us take a man in good health, whose brain and mental functions are normal. Let this man be all but killed in a railroad accident. In the jar and shock of the collision this man was thrown (let us say) against an iron post, and his head badly cut and bruised. He was knocked insensible, and it was several hours before he returned to the first dim consciousness of his surroundings. Gradually he would revive. Objects would present themselves to his eyesight vaguely, indistinctly; he would "see men as trees walking." Sounds would be heard, but indistinctly; there would be a vague jumble of noises, and no definite and articulate sounds would be recognized at first, and until consciousness was more fully restored. Tactile sensations, smell and touch, would probably come last, and be least powerful of all; they would not be even distinguishable until consciousness was almost completely normal. All intellectual interests would be abolished, only the most loving and tender thoughts would be entertained or tolerable, and these would be swallowed up, very largely, in the great, central fact that the body and head were in great pain; that the memory was impaired, and that anything like normal thinking and a normal grasp of the organism was impossible. Thoughts would be scattered, incoherent, and only the strongest stimuli would focus the attention on any definite object for longer than a few moments at a time, and perhaps even these would fail. But if oxygen gas were administered to such a person, in moderate doses, he would recover and rally far more quickly and effectually than if no such stimulant were employed. He would rally more quickly, and be enabled to think more clearly and consistently--at least _pro tem._ In shocks to the living consciousness this would almost certainly be the case.