E. F. Benson 
The Countess of Lowndes Square and Other Stories 

Cynthia, Countess of Hampshire, was sitting in an extraordinarily elaborate dressing-gown one innocent morning in June, alternately opening letters and eating spoonfuls of sour milk prepared according to the prescription of Professor Metchnikoff. Every day it made her feel younger and stronger and more irresponsible (which is the root of all joy to natures of a serious disposition), and since (when a fortnight before she began this abominable treatment) she felt very young already, she was now almost afraid that she would start again on measles, croup, hoops, whooping-cough, peppermints, and other childish ailments and passions. But since this treatment not only induced youth, but was discouraging to all microbes but its own, she hoped as regards ailments that she would continue to feel younger and younger without suffering the penalties of childhood.