One more point deserves notice before leaving this part of the inquiry, which is the specially high small-pox mortality of great commercial seaports. The following table, compiled from Dr. Pierce’s _Vital Statistics_ for the Continental towns and from the Reports of the Royal Commission for those of our own country, is very remarkable and instructive. +-------------------+-------+--------------+ | Name of Town. | Year. | Small-pox | | | | Death-rate | | | | per Million. | +-------------------+-------+--------------+ | Hamburgh | 1871 | 15,440 | | Rotterdam | 1871 | 14,280 | | Cork | 1872 | 9,600 | | Sunderland | 1871 | 8,650 | | Stockholm | 1874 | 7,916 | | Trieste | 1872 | 6,980 | | Newcastle-on-Tyne | 1871 | 5,410 | | Portsmouth | 1872 | 4,420 | | Dublin | 1872 | 4,330 | | Liverpool | 1871 | 3,890 | | Plymouth | 1872 | 3,000 | +-------------------+-------+--------------+ The small-pox death-rate in the case of the lowest of these towns is very much higher than in London during the same epidemic, and it is quite clear that vaccination can have had nothing to do with this difference. For if it be alleged that vaccination was neglected in Hamburgh and Rotterdam, of which we find no particulars, this cannot be said of Cork, Sunderland, and Newcastle. Again, if the very limited and imperfect vaccination of the first quarter of the century is to have the credit of the striking reduction of small-pox mortality that then occurred, as the Royal Commissioners claim, a small deficiency in the very much more extensive and better vaccination that generally prevailed in 1871, cannot be the explanation of a small-pox mortality _greater_ than in the worst years of London when there was no vaccination. Partial vaccination cannot be claimed as producing marvellous effects at one time and less than nothing at all at another time, yet this is what the advocates of vaccination constantly do. But on the sanitation theory the explanation is simple. Mercantile seaports have grown up along the banks of harbours or tidal rivers whose waters and shores have been polluted by sewage for centuries. They are always densely crowded owing to the value of situations as near as possible to the shipping. Hence there is always a large population living under the worst sanitary conditions, with bad drainage, bad ventilation, abundance of filth and decaying organic matter, and all the conditions favourable to the spread of zymotic diseases and their exceptional fatality. Such populations have maintained to our day the insanitary conditions of the last century, and thus present us with a similarly great small-pox mortality, without any regard