Abstract

References
1.
Bray
J
. (1945 ) J. Path. Bact.
57 , 239 .
2.British Medical Journal (1968 ) i , 715 .
3.
Giles
C
Sangster
G
Smith
J
. (1949 ) Arch. Dis. Childh.
24 , 45 .
4.
Hughes
M H
Greaves
J L
Bettelheim
K A
. (1968 ) J. clin. Path.
21 , 387 .
5.
Jacobs
S I
Holzel
A
Wolman
B
Keen
J H
Miller
V
Taylor
J
Gross
R J
. (1970 ) Arch. Dis. Childh.
45 , 656 .
6.
Jamieson
R S
. (1956 ) Med. Offr
95 , 331 .
7.Lancet (1968 ) i , 32 .
8.
Mann
N M
Ross
S
Patterson
W H
. (1952 ) Arch. Dis. Childh.
27 , 457 .
9.
Rogers
K B
Koegler
S J
. (1951 ) J. Hyg. (Camb.)
49 , 152 .
10.
Scott
J A
. (1953 ) Brit. J. prev. soc. Med.
7 , 194 .
11.
Taylor
I
. (1954 ) Lancet
i , 202 .
12.
Taylor
J
Powell
B W
Wright
J
. (1949 ) Brit. med. J.
ii , 117 .
13.
Taylor
J
Wilkins
M P
Payne
J M
. (1961 ) Brit. J. exp. Path.
42 , 43 .
14.
Thomson
S
Watkins
A G
Gray
O P
. (1956 ) Arch. Dis. Childh.
31 , 340 .
15.
Winton
F W
Keay
A J
. (1968 ) J. Hyg. (Camb.)
66 , 325 .
