The heart is frequently made more rapid and the blood pressure is certainly raised in an ordinary smoker, while even a novice may get at first an increase, but soon he may become depressed and have a lowering of the pressure. While a moderate smoker may have an increase of 10 mm. in blood pressure, an excessive smoker may show but little change. Perhaps this is because his heart muscle has become weakened. If the person's blood pressure is high, the heart may not increase in rapidity during smoking, and if he is nervous beforehand and is calmed by his tobacco, the pulse will be slowed. It has been shown that the blood pressure and pulse rate may be affected in persons sitting in a smoke-filled room, even though they themselves do not smoke. The length of time the increased pressure continues depends on the person, and it is this diminishing pressure that causes many to take another smoke. The heart is slowed by the action of nicotin on the vagi, as these nerves are stimulated both centrally and peripherally. An overdose of nicotin will paralyze the vagi. The heart action then becomes rapid and perhaps irregular. The heart muscle is first stimulated, and if too large a dose is taken, or too much in twenty-four hours, the muscle becomes depressed and perhaps debilitated. The consequence of such action on the heart muscle, sooner or later, is a dilation of the left ventricle if the overuse of the tobacco is continued. There is, then, no possible opportunity for any discussion as to the action of tobacco on the circulation. Its action is positive, constantly occurs, and it is always to be considered. The only point at this issue is as to whether or not such an activity is of consequence to the individual. The active principle of tobacco is nicotin, besides which it contains an aromatic camphor-like substance, cellulose, resins, sugar, etc. Other products developed during combustion are carbon monoxid gas, a minute amount of prussic acid and in some varieties a considerable amount of furfurol, a poison. From any one cigar or cigaret but little nicotin is absorbed, else the user would be poisoned. It is generally considered that the best tobacco comes from Cuba, and in the United States from Virginia. While it has not been definitely shown that any stronger narcotic drug occurs in cigarets sold in this country, it still is of great interest to note that a user who becomes habituated to one particular brand will generally have no other, and the excessive cigaret-smoker will generally select the strongest brand of cigarets. The same is almost equally true of cigar smokers.