Abstract

References
1.
Fry
J.
(1958 ) Brit. med. J. , i , 259 .
2.
Guthrie
J.
Forsyth
D. M.
Montgomery
H.
(1957 ) Lancet , ii , 590 .
3.
Holland
W. W.
(1957 ) Lancet , ii , 840 .
4.Ministry of Health (1956 ) Mon. Bull. Minist. Hlth. Lab. Serv. , 15 , 226 .
