It is not our intention at present to enlarge on the causes of disease, yet we maintain, that such a relation as that referred to, will in almost every instance be made out, if candid and efficient inquiry be instituted; so that, even granting that atmospheric contagion exists, there can be no room for its operation. And we are of opinion, that if, in some extraordinary instance, no such relation can be detected, the progress which every department of science is making will in time achieve what may not be accomplished at present. The history of nations and the records of medicine shew, that, coincident with epidemic sickness, there have, for the most part, been noticed certain circumstances operating which were prejudicial to the welfare of the human body. For example, famine, bad or unwholesome food, great and long continued droughts, great rains followed by intense heat, sudden vicissitudes of weather, dissipation, irregularities, depressed state of mind, insufficient clothing and fuel, and unwholesome water. These, and many similar circumstances known to prevail in the haunts of pestilence, must exert a great, a very powerful, influence on the human body, and, when the question of the probable causes of its diseases is mooted, it argues a strange and discreditable blindness to obvious facts, to overlook the part which they must exert in their production; and a strong and dangerous partiality to a questionable principle, to attribute the whole calamity to atmospheric contagion. CHAPTER II. THE EVIDENCE DRAWN FROM DISEASE ATTACKING THE RELATIVES, ATTENDANTS, AND VISITORS OF THE SICK, IN FAVOUR OF ATMOSPHERIC CONTAGION, CONSIDERED—FACTS EXPLAINED. Few points have been held so conclusive of the existence of atmospheric contagion, as the circumstance of the attendants and visitors of the sick being attacked with the same distemper, during, or shortly after, their communication. It is vain to deny, that where a person is ill of a disease, such as fever, that those about him, the members of his family, his attendants, and his visitors, are sometimes attacked with the same distemper. Such is a common occurrence, but common as it is, it cannot prove that the efficient cause is atmospheric contagion. Were it established that atmospheric contagion existed in that individual disease, and in that individual case, then it might be admitted that the circumstance did lend some countenance to the supposition, and should perhaps entitle the case to examination. But it has never been shown that that principle positively exists. There is, as has already been observed, no proof, saving that drawn from the very circumstances for which it is called in to account. Thus it is entitled to no exclusive respect.