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ABSTRACTS
[Vol. XXV, Part II,
by vaccines. The two species of organisms differ widely in their cultural, serological
and biochemical properties.
According to the author, a careful examination should be carried out on isolating
the pleuropneumonia-like organisms from the goats to study their properties, so
that they may be accurately identified and the organism of contagious pleuropneu-
monia of goats may not be mistaken for the organism of contagious agalactia.
Further, it was shown that pathologically caprine pleuropneumonia resembled
bovine pleuropneumonia and that the causal organisms of the two said diseases
possessed similar cultural properties. The complement fixation test also indicated
that they might have common antigens. In two of their properties, the decolouriza-
tion of horse erythrocytes by the supernatant from a six-day fluid culture and
liquefaction of inspissated serum, they differed from all other organisms of the
pleuropneumonia group. The organisms may, therefore, according to the author,
not belong to two different species but may be two varieties of one-species. (C.L.S.)
The use of culture virus in the preparation of foot and mouth disease vaccine.
W.M. HENDERSON and IAN A. GALLOWAY (1953). J. Hyg., 51. 546-558
T HREE experiments were performed for the preparation of vaccines for the
immunization of cattle against foot and mouth disease and the efficacy of
vaccine prepared from virus passaged in cattle, compared with vaccine prepared
from virus passaged in culture.
In the case of virus strains in cattle, the epithelium was collected from the
tongue lesions about 20 hours after inoculating cattle intradermally into the tongue
with the suspension of cattle tongue epithelial tissue from a reactor and stored
at 4° C in equal parts of glycerine and M/25 phosphate buffer solution, pH 7.6.
The passage of virus strains in culture was carried out by collecting cattle tongue
from an abattoir and within two hours of slaughter the superficial layers of the
mucous membrane were removed by traction. The exposed deeper layer of the
mucous were collected aseptically, minced in Tyrode's solution-pH 7.6, and stored
at 4° C until required. The material for culture passages of each strain consisted of a
Sietz filtrate of 1 : 25 suspension of virus infected epithelium from cattle tongue
lesions in a mixture of equal parts of M/25 phosphate buffer solution and Hartley's
digest broth pH. 7.6. Subsequent passages were made with the filtrate prepared
in the same way. Before each culture passage, minced tongue tissue was added
to the virus filtrate and stored at 4°C for three to four hours. About 2 gm. of tissue
was then transferred from the filtrate to 725 ml. flasks containing 45 ml. Tyrode's
solution, 5 ml. normal cattle serum and 50,000 units of Na-penicillin. Air in the
flasks was replaced with 95 per cent oxygen and 5 per cent CO 2 , the flasks were
sealed and incubated at 37°C for 18-24 hours. The maximum infectivity of the
tissue was reached at about 18-24 hours incubation. After inoculation, tissue was
separated from the culture by centrifugation and pooled.
The virus content of the infective material was estimated by multiple inoculation
technique of Henderson,