In the course of an important discussion which took place between Sir Ranald Martin, Mr Solly, Dr Ranking, and other scientific physicians, the following important results were arrived at respecting smoking: (1) That the habit is only prejudicial when carried to excess; (2) that tobacco is innocuous as compared with alcohol, and in no case worse than tea, and by the side of high living, contrasts most favourably. Whether smoking is or is not injurious to health depends principally upon the following conditions: (1) The kind of tobacco smoked; (2) the manner in which it is consumed; (3) the amount of tobacco smoked; and lastly, when it is indulged in. The great object is to obtain a tobacco which possesses the smallest percentage of nicotine. It was formerly believed that the best varieties of Havana and Turkish tobacco were the most innocuous. According, however, to the recent exhaustive researches of Dr George Harley, F.R.S., it appears that the more delicate the aroma of tobacco, the more poisonous it becomes. Dr Harley is also of opinion that ‘Caporal’ tobacco contains _least nicotine_, and is consequently to be preferred by those desirous of health. Pipes made of clay, and meerschaums—not foul—are, Dr Richardson considers, in a hygienic point of view, superior to cigars and cigarettes. Neither cigars nor cigarettes should ever be smoked near the end, as the nicotine then is discharged into the mouth in larger proportions. M. Melsens, a very distinguished chemist, is of opinion that a plug of cotton-wool saturated with a solution of strong citric or tannic acid should be inserted in the stem of the pipe, cigar, or cigarette holder. By this precaution, the smoke is effectually filtered, ere reaching the mouth, as the nicotine would then be seized by and combined with the acid. Those who object to this plan on account of its trouble, might with advantage place a small piece of plain cotton-wool in the stem of their pipe as a filtering agent. This should on each occasion be removed and replaced by a fresh one. A more convenient, and probably not less effective plug, is a bit of paper crumpled into a soft ball and placed in the bottom of the pipe. It acts as an absorbent of the objectionable juices which might otherwise find their way into the mouth, and can be changed, if the smoker chooses, every time he fills his pipe.