With regard to the use of alcohol and tobacco, I do not think any general rule can be laid down. Some powerful thinkers are very considerable smokers, while other powerful thinkers would have been damaged, if not ruined, by the practice. A similar remark applies in the case of alcohol. In my opinion, the man is happiest who is so organised as to be able to dispense with the use of both. JOHN TYNDALL. Feb. 14, 1882. MR. IVAN TOURGUENEFF. In answer to your enquiry I have to state that I have no personal experience of the influence of tobacco and alcohol on the mind, as I do not smoke or use alcoholic drinks. My observations on other people lead me to the conclusion that tobacco is generally a bad thing, and that alcohol taken in very small quantities can produce a good effect in some cases of constitutional debility. Iv. TOURGUENEFF. March 14, 1882. MARK TWAIN. I have not had a large experience in the matter of alcoholic drinks. I find that about two glasses of champagne are an admirable stimulant to the tongue, and is, perhaps, the happiest inspiration for an after dinner speech which can be found; but, as far as my experience goes, wine is a clog to the pen, not an inspiration. I have never seen the time when I could write to my satisfaction after drinking even one glass of wine. As regards smoking, my testimony is of the opposite character. I am forty-six years old, and I have smoked immoderately during thirty-eight years, with the exception of a few intervals, which I will speak of presently. During the first seven years of my life I had no health--I may almost say that I lived on allopathic medicine, but since that period I have hardly known what sickness is. My health has been excellent, and remains so. As I have already said, I began to smoke immoderately when I was eight years old; that is, I began with one hundred cigars a month, and by the time I was twenty I had increased my allowance to two hundred a month. Before I was thirty, I had increased it to three hundred a month. I think I do not smoke more than that now; I am quite sure I never smoke less. Once, when I was fifteen, I ceased from smoking for three months, but I do not remember whether the effect resulting was good or evil. I repeated this experiment when I was twenty-two; again I do not remember what the result was. I repeated the experiment once more, when I was thirty-four, and ceased from smoking during a year and a half. My health did not improve, because it was not possible to improve health which was already perfect. As I never permitted myself to regret this abstinence, I experienced no sort of inconvenience from it. I wrote nothing but occasional magazine articles during pastime, find as I never wrote one except under strong impulse, I observed no lapse of facility. But by and by I sat down with a contract behind me to write a book of five or six hundred pages--the book called "Roughing it"-- and then I found myself most seriously obstructed.