25 FEBRUARY 1949, Page 18

SPARROWS AND D.D.T.

SIR,—Sir William Beach Thomas, in his notes of January 14th, asks, " How do sparrows detect D.D.T. ? " In this country the answer is that they don't. This house has been sprayed with residual D.D.T. four times in the last 24 months, but neither my neighbours nor I can keep the sparrows out, and, mark you, these houses are supposedly wired against mosquitoes. It cannot be argued that the D.D.T. is at fault, as we are completely free from both mosquitoes and flies. But sparrows ? No, Sir.—Yours, &c., C. B. DREW

(Province Medical Inspector).

Wad Medani, Blue Nile Province, Sudan.