Before leaving this subject, I think it right very briefly to allude to an argument which is often objected to the view here stated. The objector looks to a particular district, or to a particular slaughter-house, and says that the mortality of the district is an average one; or he points to Mr. A. or Mr. B.--the butcher or the butcher’s man, saying, ‘Who can be healthier than A. or B.? Surely, if the pursuit be injurious, these men ought to have been poisoned long ago.’ Now, to this I reply;--first, as regards the men employed in these crafts, we have no statistics of any value to decide on their mortality, and judgment on the matter cannot be deduced from some half-dozen cases, known to any of us individually; but, further, if we admit (which I by no means know to be the case) that they are persons of average longevity and healthiness, then it must be remembered that their activity, their out-door exercise, and, above all, their unlimited supply of animal food, are circumstances conducing to give them health beyond the average of their station; and it must be remembered that these palliating circumstances, though they may counteract the evil for those persons most nearly concerned in it, contribute nothing towards deodorising the neighbourhood, or towards preserving its poorer inhabitants from the depressive influence of putrid emanations. And, as regards the district--although we have certain evidence that organic decomposition is a chief cause of disease, yet we do not invariably find disease generated in immediate proximity to the source of nuisance. Drainage beneath the soil, and currents of air above it, convey the materials of decomposition to a distance; and if the particular slaughter-houses be placed on a high level amidst the surrounding City, so that their drainage be effectual and their ventilation complete, then obviously their influence must be sought for, not so much in any special aggravation of the local mortality, as in certain remoter effects of their diffused emanation; in effects, namely, which are discoverable along their lines of drainage and ventilation, and in the various consequences of a highly zymotic atmosphere generally through the entire town. * * * * *