Sir, I, too, was in Deolali (letters, July 26 and 31) 60 years ago, while serving with the Royal Army Medical Corps.
I cannot do better than to provide an extract from Brewer’s Concise Dictionary of Phrase and Fable (Cassell, 2000):
Doolalli (Doolally) or Doolalli tap. An army expression for an unbalanced state of mind or mental derangement . . . Tap when used in conjunction is the E. Indian word for fever.
Yours faithfully,
C. MATTISON,
8 Cricketers Court,
Fox Road, West Bridgford,
Nottingham NG2 6AR.
August 6.