Mordach Mackenzie, Philosophical Transactions of the Royal Society (1765)
“ It is beyond dispute, that the plague appears in a different manner in different countries; and that it appears differently in the same country in different years: for we find most other diseases alter more or less, according to the constitution and disposition of the air in the same climate: for, some years, fevers are epidemic, and very mortal: other years, they are epidemic, but not mortal ”
