1. ATKINSON, F. R. B., and WEBER, F. P. (1938), Brit. J. Derm., o5, 267.
2. BRIGGS, J. N., and ILLINGWORTH, R. S. (1952), Lancet, ii, 800.
3. BROOKS, W. D. W. (1934), Quart. J. Med., 3, 293.
4. quoted by CECIL (1955), ' A Textbook of Medicine';B.U.R.N.E.T.T.;Philadelphia. Saunders
5. Guy's Hosp;COLE, W.R.;Rep,1953