The slow progress from west to east has been made much of by Defoe, who used the bills of mortality to ascertain the rise of the infection in the several districts. His conclusion is the same in the main as Boghurst’s contemporary observation; only that he makes the infection of Southwark later, and with reason so far as the bills show:—
“It was now mid-July, and the plague which had chiefly raged at the other end of the town, and as I said before, in the parishes of St Giles’s, St Andrew’s, Holbourn, and towards Westminster, began now to come eastward towards the part where I lived. It was to be observed, indeed, that it did not come straight on toward us; for the City, that is to say within the walls, was indifferent healthy still; nor was it got then very much over the water into Southwark; for though there died that week 1268 of all distempers, whereof it might be supposed above 900 died of the plague [only 725 in the bill], yet there was but 28 in the whole City within the walls, and but 19 in Southwark, Lambeth included; whereas in the parishes of St Giles’ and St Martin’s in the Fields alone, there died 421.... We perceived, I say, the distemper to draw our way; viz. by the parishes of Clerkenwell, Cripplegate, Shoreditch, and Bishopsgate; which last two parishes joining to Aldgate, Whitechapel and Stepney, the infection came at length to spread its utmost rage and violence in those parts, even when it abated at the western parishes where it began. It was very strange to observe that in this particular week, from the 4th to the 13th July, when, as I have observed, there died near 400 of the plague in the two parishes of St Martin’s and St Giles’ in the Fields only, there died in the parish of Aldgate but four, in the parish of Whitechapel three, and in the parish of Stepney but one.” In the following week of July, with a total of 1761 deaths, whereof of the plague 1089, only 16 occurred on the Southwark side. Soon, however, Cripplegate had the infection at its hottest, and at the same time Clerkenwell, St Sepulchre’s parish, St Bride’s and Aldersgate. “While it was in all these parishes, the City and the parishes of the Southwark side of the water, and all Stepney, Whitechapel, Aldgate, Wapping and Ratcliff were very little touched; so that people went about their business unconcerned, carried on their trades, kept open their shops, and conversed freely with one another in all the City, the east and north-east suburbs, and in Southwark, almost as if the plague had not been among us.”
In another passage Defoe brings out the moral of its gradual advance. He had shown
“how it began at one end of the town, and proceeded gradually and slowly from one part to another; and like a dark cloud that passes over our heads, which as it thickens and overcasts the air at one end, clears up at the other end: so while the plague went on raging from west to east, as it went forwards east it abated in the west, by which means those parts of the town which were not seized, or who were left, and where it had spent its fury were, as it were, spared to help and assist the other; whereas had the distemper spread itself all over the City and suburbs at once, raging in all places alike, as it has done since in some places abroad, the whole body of the people must have been overwhelmed” etc.
That is how Defoe constructs a concrete picture from the dry statistics of the weekly bills. He has defined the stages, and pointed the moral, with a firmer hand than the reality would most likely have warranted. But no scientific writer could have apprehended more correctly the general fact of a gradual invasion from the west end of the town.
These striking facts of the gradual advance of the Great Plague of London from west to east will be found to suit that theory of the plague-virus which has been illustrated in various parts of this volume. The virus of plague is a soil-poison, or the ground is its habitat; its quiescence or activity depends upon whether or not the state of the soil favours the fermentation of the special organic matters therein, which special organic matters we here take to be the products of cadaveric decomposition. The conclusion that the poison of plague lay in the soil, and that it rose into the air in emanations or effluvia, was forced upon all those who thought much about the matter from the medieval period onwards. Thus, the apothecary Boghurst, says in his first chapter: “And therefore my opinion falls in wholly with those who make the earth the seminary and seed-plot of these venomous vapours and pestiferous effluvia, which vitiate and corrupt the air, and consequently induce the pestilence.” And again: “The plague is a most subtle, insinuating, venomous, deleterious exhalation, arising from the maturation of the ferment of the forces (?) of the earth, extracted into the air by the heat of the sun.” It is true that Boghurst, like the sixteenth-century writers abroad, such as Ambroise Parè, locates the venom in mysterious cavities and bowels of the earth, and dwells upon the agency of earthquakes in setting it free. But he comes to more ordinary causes in his enumeration of favouring things—“dunghills, excrements, dead bodies lying unburied, putrefying churchyards too full,” and again “breaking up tombs and graves where dead bodies have been long buried.” As telling against the last, however, he adds: “When the charnel-house at St Paul’s was demolished, there was a thousand cart-loads of dead men’s bones carried away to Finsbury, yet no plague followed it.”
The activity of this soil-poison depends upon processes in the soil which go on so slowly that the link of cause and effect is easily overlooked. In the last resort, they are dependent on the rise and fall of the ground-water. It was observed beyond all doubt as the law in Lower Egypt, that the plague came forth annually after the Nile had begun to fall, and that it reached its height in the months of March, April and May, when the soil was driest, or the pores of the ground occupied solely by air after having been full of water. It was observed, also, that the plague-area and the inundation-area were co-extensive. Lower Egypt is, of course, somewhat peculiar (Lower Bengal coming near to it) in these regular alternations of air alone and water alone in the pores of the ground. But other countries have the same sharp contrast occasionally, and London had the contrast very decidedly in the years 1664 and 1665. The months from November 1664 to June 1665, some of which ought to have brought snow or rain to raise the wells and springs to their highest periodic water-mark early in the year, were quite remarkable for drought: Richard Baxter says that no one remembered the like. The ground-water, instead of rising all through the winter, must have fallen lower and lower as the spring and summer advanced. The pores of the ground had been occupied with air to an unusual depth of the subsoil, and the presence of air in these circumstances had given occasion to that ferment-activity in the special organic matters of an old-inhabited soil which produced the virus of plague. The stratum of subsoil would become dry first in the more elevated parts; and as the ground-water continued to fall, the air would reach in due course an unwonted stratum in the lower situations. Defoe says that they came to water at eighteen feet in digging the Whitechapel plague-pits. The same seasonal march of a soil-infection from the higher ground to the lower has been observed in modern times in other cities, and in other diseases than plague. The drought for seven months from November to June would not, of itself, have caused a great plague. But it was an essential member of the co-operating group of things; and it probably determined of itself the season when the great plague was once more to come and take away the enormous increase of poor people.
Mortality and Incidents of the Great Plague.
The plague of 1665 was justly called the Great Plague, and is sometimes spoken of as “the plague of London,” as if it were unique. But it was not much more severe than those of 1603 and 1625 had been for the London of their generation; and there had been many plagues when London was a small capital, such as those of 1407, 1479, 1500, 1513 and 1563, which had cut off as large a proportion (one-fifth to one-sixth) of the population. The inhabitants in 1665 were not far short of half a million, nearly twice as many as in 1603, and about a third more than in 1625. The increased mortality in 1665 was somewhat more than proportionate to the increase of inhabitants, as the following table shows:—
| Year | Estimated population | Total deaths | Plague deaths | Highest mortality in a week | Worst week | |||||
| 1603 | 250,000 | 42,940 | 33,347 | 3385 | 25 Aug.-1 Sept. | |||||
| 1625 | 320,000 | 63,001 | 41,313 | 5205 | 11-18 Aug. | |||||
| 1665 | 460,000 | 97,306 | 68,596 | 8297 | 12-19 Sept. |