From a careful attention to all these histories, it is plain that the plague is naturally an eruptive disease, as, in all the animals in which it was artificially brought on, eruptions took place, provided the life of the creature was sufficiently prolonged to allow them to come out. Dr. Russel says, that, from his diary, he noted down the cases of _two thousand seven hundred_ patients, _all_ of whom had eruptions of one kind or other. In this it agrees with the small-pox, which Dr. Mead justly considers as an inferior kind of plague. In the latter, however, the eruptions seem to resemble those called by Dr. Hodges the _tokens_, only that the cause which produces them is less violent in its nature; but why the eruptions of the small-pox should be in distinct pustules, and not one continued boil all over the body, is undoubtedly inexplicable on any theory whatever. The same is true of the plague. No man can explain why the tokens, for instance, instead of being collected into one great eschar, are dispersed into small distinct pieces; or why, instead of buboes in the groin and armpit, or instead of carbuncles in different parts of the body, there should not be a single one equivalent in bulk and power to them all. This appears similar to the phenomena of rain, hail or snow, which fall in distinct drops, fluid or congealed, or in flakes, instead of being equally diffused all over the spot on which they fall. In the latter case we say that the phenomenon is occasioned by _electricity_: we may say the same, if we please, of the small-pox and plague, with equal emolument. From the accounts we have just now quoted, it appears that there is between malignant fevers and the true pestilence a very essential difference; the latter tending to thicken the blood, the former to make it thinner. In this respect therefore the poisons seem to resemble malignant fevers very considerably; for M. Fontana observed that by mixing animal poisons with blood drawn from a vein, it was prevented from coagulating. In the instance above related where a dog died in consequence of bile injected into his veins from one who died of a malignant fever, the blood was found extremely fluid. In some who died of the hospital fever, Sir John Pringle informs us, that suppurations had taken place in the brain; but in the true plague the tendency to mortification always prevailed above every thing.