The public ledger. [volume] (Maysville, Ky.) 1913-1968, 1916-06-19
NEW METHOD OF MAKING ANTI.
HOG.CHOLERA SERUM

Washington, ID. CA new method OF
preparing anti-hog-cholera serum,
which permits the economical produc-
ton of a clear sterilized product, has
just been described in the Journal of
Agricultural Research of the U. s. De-
partment of Agriculture. The advant-
age claimed for the new method is that
it makes possible the production of an
anti-hog-cholera serum which can be
quickly sterilized by heat to a point
that will absolutely kill any germs of
foot-and-mouth disease and so yield
serum that is absolutely safe even If
taken from a hog which might harbor
foot-and-mouth disease and yet give no
Indication of being infected.
The method, as described by its dis
coverers, DR.. Marion Dorset and r. r.
Henley. of the Biochemic Division. Bu-
reau Of Animal Industry. consists in
adding slight amount of an extract
from ordinary white navy beans 20 the
defibrinated hog-cholera- immune blood
which has been the form of the serum
used in the past. The addition of this
bean extract causes the red cells of
the blood to agglutinate and when the
mixture is whirled on a centrifuge the
red cells pack together and form a
rather stiff jelly-like mass. 1t is then
possible to pour off clear serum, leav
ing behind the red cells which play no
part in preventing hog cholera and
which in fact simply tend to dilute the
serum and render its sterilization by
neat impracticable. To increase the
yield Of clear serum the dlscoverers
added a small amount OF ordinary salt
and found that they obtained from 70
to "a per cent of clear serum. The
clear serum thus obtained It was found
could be heated for 80 minutes at a
Temperature OF 60 degrees CentiEade
without changing its consistency or
lessening in any way its effectiveness
in preventing how cholera. The heat
ing to this point for this time is more
than sufficient to kill any germs Of
foot-and-mouth disease which might
accidentally be present. Practical tests
with hogs show that probably all OF
the antibodies useful in combating hog
cholera were retained In the serum
and the red cells extracted contained
so few, If any, of these valuable bodies
as TO make the residue OF red cells use
less In preventing the disease
Before the clear serum was de-
veloped, army attempts we're made 10
sterilize by heat in practicable way
the ordinary defibrinated blood. II was
found. however, that heating the old
product up to so degrees Centigrade
resulted in more or less complete coag-
ulation Of the defbrinated blood and in
the destruction Of the serum 30 far as
its commercial worth is concerned. III
was found that the highest temperature
that could be used was 90 degrees
Centigrade and II was necessary TO
keep the old serum at this temperature
for IL hours TO make certain that the
virus OF foot-and-mouth disease was
killed. Heating serum at a steady tenn
perature over this long period IN or
binary pratices is dificult an dtoo ex-
pensiye.
Attempts also we're made 20 make a
clear serum by centrifugalizing. Il was
found however. that while the eentri-
fuge would separate TO some extent the
red cells. they were in such shape that
Il was dificult 70 separate the serum
completely An important quantity -
antlbOdles were len behind In the red