Nature, in the first compounding and forming of us, hath laid into the Substance and Constitution of each something equivalent to Ovula, of various distinct Kinds, productive of all the contagious, venomous Fevers, we can possibly have as long as we live.
Exanthematologia: Or, An Attempt to Give a Rational Account of Eruptive Fevers, Especially of the Measles and SmallPox (1730)