Views of an opposite character as to its use have long prevailed. Much has been written in relation to its baneful effects upon the human system, the active poisons it is known to contain, and its demoralizing tendencies in general. It has been accused of being the cause of numerous diseases of a grave nature, such as cancer, chronic bronchitis, insanity, diseases of the throat and the mucous membranes of the mouth and nose, etc., etc. It bears the blame of causing filthy, and ofttimes disgusting, habits, and of being not only a useless but a pernicious and expensive luxury. On the other hand, much has been and continues to be said as to its comforting and soothing effects, and the sense of enjoyment and luxury resulting from it, when used in the form of smoke and with moderation. And if an opinion as to its excellencies and value to the human race could be formed from the amount yearly consumed, or the vast sums of capital invested in its culture, manufacture, and sales in the United States alone, it would take rank as an article possessed of the highest value to mankind. This, however, cannot be considered as a fair criterion by which to judge of its virtues or its vices; neither can we look for an impartial judgment as to its influence upon individuals or society, from those who may form opinions founded on impressions or prejudices only. It becomes necessary, therefore, to study its physiological effects as accurately and impartially as possible, and accept such results as this course may lead to. For my present purpose it does not become necessary to go into details as to the effects of all the elements of tobacco, or of the effects of any of these elements, except as observed in their action upon the nervous system. I shall not, therefore, enter upon any minute analysis of the substance, preferring to leave this for those who write with a view of covering a more extended field of research. When tobacco, in substance, or in the form of smoke, comes in contact with the mucous membrane of the mouth, throat, and nose, there results a more or less distinct biting sensation on the tongue and in the throat, unless these parts have already become accustomed to its effects. This increases in the case of the beginner, until in a few minutes a feeling of warmth and faintness comes on, often attended with nausea, vomiting, and headache. If the dose has been sufficient, the person becomes faint and unable to stand, the skin becomes cool, a perspiration appears on the forehead, the heart acts feebly, the respiration is short and hurried, and life itself is in danger.[19]