George Saintsbury (1845-1933), Notes on a Cellar-Book
(London: Macmillan and Co., Limited, 1920), pp. 122-123:
Everybody knows that hot rum and water is sovereign for a cold, but perhaps everybody does not
know exactly how the remedy should be applied.
This is the probatum. You must take it in bed;
premature consumption merely wastes the good
creature. It should be made, in a large rummer-glass, as hot as you can drink it (hence the advice
of the rummer—for a mere tumbler may burn
your hands), not too sweet, but so strong that you
sink back at once on the pillow, resigning the glass to the ready hands of a sympathising bedside
attendant, preferably feminine.