Evening times-Republican. [volume] (Marshalltown, Iowa) 1890-1923, 1916-06-14
Ne,U Method For
Manufacture of Anti
Hog Cholera Serum

A new method Of preparing anti hog
cholera serum, which permits the econ
omical production of clear sterilized
product, has just been described in the
Journal of Agricultural Research of the
United States department of agricul-
ture. The advantage claimed for the
new method is that 1t 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 nd mouth dis
ease and so yield serum that is abb
solutely safe even II taken from hog
which might harbor foot-and- mouth
disease and yet give no indication OF
being infected.
The method, as described by it's dis
coverers. DIR. Marion Dorset and r. r.
Henley. OF the biochemic division, bu-
reau of animal industry, consists in
adding n slight amount of an extract
from ordinary white navy beans to the
defbrinated 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
bleed &C :Ss'atinate and when the mix
ture Is whirled on centrifuge the red
cells pack together and form n rather
stlff Jeliy-like mass. 1t is then possible
to pour off a clear serum leaving be j.
hind 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 heat i'm
I practicable. To increase the Yield OF
clear serum the discoveries added a
small amount of ordinary salt and
found that they obtained from 70 to "a
I per cent of clear serum. The clear Sc
rum thus obtained it was found could
be heated for thirty minutes at tenn
perature of go degrees centigrade with
out changing its consistency or lessen
ing in any way its effectiveness in pre-
venting hog cholera. The heating to
this point for this time is more than
sufficient to kill any germs OF foot
and mouth disease which might acct
dentally be present. Practical tests
with hogs show that probably all of
the anti-bodies useful in combating
hog cholera were retained in the serum
and the red cells extracted contained so
few. IL any, of these valuable bodies as
TO make the residue of red cells useless
In preventing the disease.
Before the clear serum was devel-
oped, many attempts were made to
sterilize by heat in a practicable way
the ordinary defibrinated blood. 1t was
found, however, that heating the old
product up to 60 degrees centigrade re-
suited in more or less complete coagn-
lation Of the defibrinated blood and in
the destruction of the serum so far as
it's commercial worth is concerned. 1t
was found that the highest temperature
that could be used was so degrees CEN
tigrade and 1t 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 temperature
over this long period in ordinary prac-
tice 10 difficult and too expensive.
Attempts also were made to make q
clear serum by certrifugalizing. 1t was
found, however. that while the centri-
fuge would separate to some extent the
red cells. they were In such shape that
1t was difficult to separate the serum
completely. An important quantity OF
anti bodies were left behind in the red
clot and the resulting product was a
cloudy rather than clear serum. With
this process. moreover. 1t was possible
ordinarily to secure only about so per
cent Of serum. Under the new method
1t is possible to secure as high as "a
per cent OF clear serum. which in ac-
tual test has proved to be fully po-