Abstract

References
1.
Brockbank
W.
(1955 ) Proc. R. Soc. Med. , 48 , 509 .
2.
Douglas
J. W. B.
(1951a ) Lancet , ii , 440
3.
Douglas
J. W. B.
(1951b ) Popul. Stud. , 5 , 35 .
4.
Ellis
M.
(1954 ) Modern Trends in Ear, Nose and Throat Practice. London, p. 227 .
5.Gray's Anatomy (1955 ) 30th ed. , 1190 –1192 .
6.
Illingworth
R. S.
(1953 ) The Normal Child. London.
7.
Russell
H. G. B.
(1955 ) Proc. R. Soc. Med. , 48 , 519 .
8.
Watson
G. I.
(1955 ) Brit. med. J. , i , 5 .
9.
Wright
S.
(1952 ) Applied Physiology.
9th ed. London, p. 805 .
