be one of the mildest; if a pipe, the tobacco will have to be the very lightest.  Anything exceeding their allowance is an excess for which they are obliged to pay the penalty.  Then, again, there is a third class who can enjoy tobacco in moderation.  But these are the very people who are most apt to abuse their privilege.  And although they do not recognise it at once, the effect of their excessive smoking is bound to assert itself at last, and compel them to curtail their allowance.  If those in the second category, who can enjoy the mildest tobacco in the smallest quantities, and those in the third, who can smoke in moderation, were never to exceed their proper amount, no very great harm would follow.  But it most frequently happens that both overstep their respective bounds, and the result is injury to health.

The tobacco plant, Nicotiana TOBACUM, belongs to the order Solanaceae, which also includes belladonna, capsicum, henbane, and likewise the common potato.  Its active principle, an alkaloid—­nicotine or nicotia —­is combined with a vegetable acid.  Some of the alkaloids, such as morphine, strychnine, &c., are crystalline in character, but this, along with a few others, is liquid.  A single drop of it is fatal to the smaller animals, a cat or Even as it is, the first smoke usually produces characteristic results.  There is generally pallor of the face, nausea, and vomiting.  Usually a cold, clammy sweat breaks out, and the heart seems as if it were about to stop.  The system, however, gradually becomes habituated to its action, and these symptoms do not reappear.  Seeing that this somewhat unpleasant apprenticeship is uncomplainingly served, it is evident that in smoking there must be some powerful attraction.  There are many, indeed, who persist in it when it is doing them an inconceivable amount of injury.

It is a fortunate thing that almost all of the nicotine passes off, or is burnt up, or else the effect would be more markedly disastrous.  But the pleasurable effects of tobacco are derived in great part from the volatile alkaloids formed during combustion.  The alkaloids which develop during the smoking of a pipe are entirely different from those of a cigar.  In a pipe, according to Vold and Eulenburg, the tobacco yields a very much larger proportion of volatile bases, especially of the very volatile and stupefying pyridine.  On the other hand, a cigar produces but little pyridine, but more of the less active collidine.  It is well known that very much stronger tobacco can be smoked as a cigar than as a pipe.  As a matter of fact a cigar which could be enjoyed as a cigar, would cause sickness if cut up into small pieces and smoked in a pipe.  This pyridine to which reference has just been made has lately been brought forward as a remedy for asthma.  Now, the effect of tobacco in cutting short an attack of this latter malady is, at times, very marked.  And Professor See, the eminent French physician, believes that the pyridine is the relieving agent.