From J. O. N. Hinckley
In the report on fly repellents secreted by cows
(This Week, 15 August, p 22),
entomologist Bradley Mullens of the University of California at Riverside
heralds the research as the first time that natural products have been shown to
influence fly behaviour in this way.
Not quite. This very discovery has been put to practical use for centuries.
In a recent television documentary, a visitor sitting in a room in a maharajah’s
old palace, doors and windows open, remarked on the absence of the neighbourhood
flies. A custodian explained that this was the intended result of mixing cows’
urine in the original wall plaster. Plus ça change…
London
