places where the atmosphere seemed _equally productive of the disease in those not employed in attending on sick_. This clearly makes all the difference, for there is no earthly reason why people about the sick should not be attacked, if they breathe the same atmosphere which would seem to have so particular an effect in producing the disease in others; indeed there are good reasons why, during an epidemic, attendants should be attacked in greater proportion; for the constant fatigue, night-work, &c., must greatly predispose them to disease of any kind, while the great additional number always required on those occasions, precludes the supposition of the majority so employed being _seasoned_ hospital attendants, having constitutions impenetrable to contagion. Those questions are _now_ well understood as to yellow fever, about which so much misconception had once existed. The proofs by disinterested authors (by which I mean those unconnected with quarantine establishments, or who are not governed by the _expediency_ of the case) in the West Indies, America, and other places, show this in a clear light; but the proofs which have for some time past appeared in various journals respecting the occurrences at Gibraltar, during the epidemic of 1828, are particularly illustrative. By the testimony of three or four writers, we find that _within certain points_, those in attendance on sick, in houses as well as hospitals, were attacked with the fever, in common with those who were not in attendance on sick; but that, where people remained at ever so short a distance beyond those points, during the epidemic influence, _not a single instance_ occurred of their being attacked, though great numbers had been in the closest contact with the sick, and frequently too, it would appear, under circumstances when contagion, had it existed, was not impeded in its usual course by a very free atmosphere:--_sick individuals, for instance, lying in a small house, hut, or tent, surrounded, during a longer or shorter space of time, by their relatives, &c._ A full exposure of some very curious mis-statements on these points, made by our medical chief of the quarantine, will be found from the pen of the surgeon of the 23d regiment, in the _Edinburgh Medical and Surgical Journal_, No. 106.[3] Those who are acquainted with the progress of cholera in India, must be aware how a difference in the height of places, or of a few hundred yards (_indeed sometimes of a few yards_) distance, has been observed to make all the difference between great suffering and complete immunity:--the printed and manuscript reports from India furnish a vast number of instances of this kind; and, incredible as it may appear, they furnish instances where, _notwithstanding the freest intercourse_, there has been an abrupt line of demarcation observed, beyond which the disease did not prevail. A most remarkable instance of this occurred in