212          PREPARATION OF ANTI-RINDERPEST SERUM.

The tests were controlled by 2 animals which died on the 6th
and 7th day respectively.

By reference to the table it is evident that the serum A
is much weaker than serum B. This is the reverse of what
Ruediger found. Had the serum preparing animals been able
to stand larger injections of artificial peritoneal fluid, it is very
probable that the serum would have been very much stronger
as undoubtedly the potency of Anti-Rinderpest Serum depends
to a certain extent upon the quantity of antigen injected. The
artificial peritoneal fluid is not simply a dilution of peritoneal
fluid with the potassium citrate solution. If the peritoneal
fluid be collected from an animal showing a high temperature
and vesicles and diluted down with potassium citrate solution
to give an amount of fluid equal to the quantity of artificial
peritoneal fluid that could be collected from such an animal,
and this diluted peritoneal fluid were used for hyperimmunising,
the potency of the resulting serum would be very low. Such
experiments have been carried out as have also dilutions of blood
and only under certain circumstances can a serum of any prac-
tical value be produced by simple dilutions.

During the time the potassium citrate solution is in the peri-
toneal cavity, vital processes (osmosis effusion of lymph) are
taking place, and the resulting artificial peritoneal fluid contains
a large quantity of antigen and can be used for the preparation
of a serum of practical use.

                              Conclusions.

1.    By using artificial peritoneal fluid the amount of viru-
lent material for hyperimmunising purposes is considerably
increased, and a marked saving in the cost of serum preparation
effected.

2.    The serum from animals injected with artificial perito-
neal fluid is usually weaker than the serum prepared by the
injection of blood.

3.    Artificial peritoneal fluid injections are well absorbed
and do not produce sloughing.