ABSTRACTS
261
history and the stage of gestation. Thus
Donham and Fitch would prefer to accept as
non-infected a cow showing a low agglutina-
tion titre from a herd with no positive reactors
than a non-reactor from a diseased herd.
All that has been said so far refers to the
microscopic tube agglutination test as carried
out in the laboratory.
Attention is drawn to the rapid tests which
have been evolved in other countries, parti-
cularly America. The rapid plate agglutina-
tion test is being used in at least one State
in the eradication of Brucella infection of
cattle, and in other States it is playing some
part in the control schemes. It is claimed
that with this test quantities of serum ap-
proximately equal to those used in the tube
test are employed and that the results are
very reliable. Of course, if this test were
adopted a standard antigen should be available
to all veterinarians using it, and a standard
of technique and interpretation would be
required.
CONCLUSIONS
There is no generally accepted standard for
the performance and interpretation of the
agglutination test for the diagnosis of Brucella
infection of cattle.
Some attempts have been made to evolve a
method of standardization of this test.
A standard of preparation of the bacterial
suspension should be adopted in Australia,
and the agglutinability of each batch be tested
against a standard positive serum.
The standard positive serum can be main-
tained at approximately its original titre for
some years in a dry condition.
It would be an advantage if the standard
suspension to be used throughout Australia
could be prepared in one central laboratory.
A standard technique should be adopted
throughout Australia so that the tests carried
out in different laboratories will be comparable.
Consideration should be given to the adop-
tion of the rapid methods of agglutination
testing since these would be of value to the
field officer in the initial determination of the
approximate degree of infection in a herd. It
may be possible to adopt this method as the
standard test as has been done in parts of
America.
REFERENCES
Topley, W. W. C. (1933). An Outline of Immunity,
p. 68. Edward Arnold & Co., London
Grunbaum, A. S. (1896). Lancet, London, 11. 806.
(Quoted by Arkwright)
Widal, F. (1896). Bull. Soc. méd. Hóp. Paris, 35. 13.
(Quoted by Arkwright)
—and
Sicard, M. A. (1897). Ann. Inst. Pasteur,
11. 353. (Quoted by Arkwright)
Arkwright, J. A. (1931). "A System of Bacteriology,
in Relation to Medicine." Medical Res. Council,
England 6. 381
Wright, A., and Smith, F. (1897). " Studies on Im-
munization." A. E. Wright, Archibald, Constable
& Co., London, 1909, 3. Reprinted from Lancet,
London, 1897
Birt, C., and Lamb, G. (1899). " Studies on Immuni-
zation " A. E. Wright, Archibald, Constable & Co.,
London, 1909, 3. Reprinted from Lancet, London,
1899
McFadyean, J., and Stockman, S. (1912). J. co
Path. 25. 22
Seddon, H. R. (1915). J. comp. Path., 28. 20
—
(1919). J. comp. Path., 32. 1
Stableforth, A. W. (1936). J. comp. Path., 49. 251
Frei (1937). Bull. Off. Intern. Epizoot. 14. 20
Willems, R. (1937). Bull. Off. Intern. Epizoot., 14.62
Donham, C. R. and Fitch, C. P. (1937). J. Amer.)
med. Ass. 89, 176
Kitselman, C. H. (1936). Ibid, 678
ABSTRACTS
Report on experimental commercial preparation
of butter fat at Longwarry : August to October
1941. G. LOFTUS-HILLS (1941) Report of the Coun.
Sci. Industr. Res. Australia 22
THE report deals with a description of the experimental
plant set up at Longwarry, for the larger scale manu-
facture of butter fat from surplus second grade butter
of Australia, with the use of centrifugal separation and
vacuum evaporation for the removal of water. The
butter fat was sent to Great Britain and to the
Navy. The butter was melted in half ton lots by direct
exposure to steam (25 minutes) and then allowed to pass
through two alfa-Laval No. 85 whey separators, set to give
about 55 per cent cream from whey. The flow of butter
fat from the second separator was regulated to give a
fairly cloudy, but not completely opaque, butter fat.
The butter fat from the second separator was afterward
dried by heating under reduced pressure in a modified
Vacreator unit and then passed through the Internal
Tubular type of cooler. The butter fat was settled in
a stainless steel tank and finally filled as completely as
possible, and packed in 4 gallon tins of which the 2¼"
screw top type with push in bungs was found to be most
satisfactory. At a vacuum of 28.5 to 29.0 inches of
mercury, the evaporator removed 2.0 to 2.5 per cent
of water from the fat at maximum throughout. It is
possible to dry to 0.1 per cent of moisture content, the
plant working at 1¼ tons of butter per hour. An
aproximate estimate of the general order of the working
costs reveals that the cost of the product per lb. at the
place of manufacture is equal to the cost of butter per
lb. delivered to place of manufacture 100/80.2 1.4d.
The rate of separation was markedly increased by adjust-
ing the pH of butter serum, after melting to 10.0 with
caustic soda. The use of unsalted butter did not have