In reply to your letter, I should say that tobacco has some action on the brain; but I think its action different in different people, and at different times in the same person. I think the action soothing after food, but exciting on an empty stomach. In the former case I think it promotes thinking in this way:--that the mind concentrates its attention better during the mechanical operation of "puffing", than when it is liable to be disturbed when not so occupied. For this reason I should say that smoking does help to get through work late at night. I find frequently that having commenced to write with a fresh pipe in my mouth, I go on a long time after it goes out; but as it remains in my mouth, it seems to have almost the same effect till the discovery, at some pause, that my pipe is out; and then it is a relaxation to spare a moment to refill it. I do not look upon smoking as a necessity to mental labour; but it seems to me, as a smoker, an agreeable and useful method for concentrating thought upon any subject. But I think it would be difficult to lay down any general rule for persons of different constitutions. E. POCKNELL. March 10, 1882. PROFESSOR GEORGE RAWLINSON. Although it does not appear to me that the method of your enquiry can lead to any important results, you are quite welcome to any information that I can give you on the subject. I was brought up to take daily a moderate amount of beer or wine, and have continued to do so all my lifetime, with the exception that my beer has been cut off, and I have been recommended to take a little brandy and soda-water, or whiskey and soda-water instead. I smoked an occasional cigar when I was young, but never much liked tobacco, and gave up the practice entirely when I was about five and twenty. I have never tried leaving off alcoholic liquors, being advised medically that it would probably be injurious to me to do so. I am, therefore, quite unable to say what effect my doing so would have on my powers of thought and work. GEORGE RAWLINSON. March 28, 1882. MR. CHARLES READE. Your subject is important, and your method of enquiry sound. I wish I could throw any light, but I cannot more than this. I tried to smoke five or six times, but it always made me heavy and rather sick; therefore, as it is not a necessary of life, and costs money, and makes me sick, I spurned it from me. I have never felt the want of it. I have seen many people the worse for it. I have seen many people apparently none the worse for it. I never saw anybody perceptibly the better for it. C. READE. Feb. 2, 1882. MR. THOMAS ALLEN REED.