25
were emuls fied to1 i n 1
0 and allowed to autolyse in the ice box for seven days. The emulsion was
then filtered through a Pasteur-Chamberland bougie F under a pressure varying between 2 and
3 atmospheres and the filtrate tested on guinea pigs both subdurally and subcutaneously (4.5 cc).
No symptoms either immediate or delayed followed. Autolysis of fixed virus emulsion 1 in
1 0
under toluol for 4 8 hours at 37°C was also tried, and the fluid was filtered through a Berkefeld
bougie without pressure. The filtrate caused no symptoms in guinea-pigs when introduced
subdurally or subcutaneously (15cc.).
It may fairly be concluded that no toxin of any potency is present in the fresh brains of .
animals which have died from fixed virus infection, nor can a fluid be extracted from rabic brains,
which have been subjected to a process of autolysis, which proves to be toxic in reasonable doses.
We have made numerous experiments with the object of detecting some toxic substance in the
organs of animals dead from rabies and of demonstrating the presence of some body capable of
uniting with the amboceptor contained in autirabic serum, which may be summarised shortly as
follows :
—
(1) Does fixed virus emulsion contain a body not found in normal brains which will unite
with the amboceptor of antirabic serum? We used the antirabic serum of Goat B which appeared
to destroy fixed virus in the proportion of 75 serum to 1 of brain matter, 1 in 50 filtered through
paper fixed virus and normal brain emulsions, the serum of a goat which had been treated with
sheep corpuscles and was therefore strongly haemolytic, and fresh sheep serum as complement.
The idea guiding the experiment was that the amboceptor of inactivated antirabic serum
might unite with some body in the fixed virus emulsion and be complemented with the fresh sheep
serum. This would withdraw some complement from the sheep serum and less would therefore be
available to complement the sensitized corpuscles subsequently added, and a proportional diminu
-
tion in the degree of haemolysis would be visible. In the series of tubes containing normal brain
there would be no body to unite with the antirabic amboceptor, no deviation of complement and,
it follows, complete haemolysis. In the end it happened that, while there was distinct deviation
of complement in both series owing to the presence of brain cells, there was no difference between
the two series.
This set of experiments is, it is clear, not far reaching. It merely establishes that the goat
antirabic serum used could not combine with any body in the rabbit fixed virus emulsion with
sheep serum as a complement. Variations in the source of these three ingredients might lead to
positive results.
(2) Pasteur and one or two others have noted that the blood of animals suffering from rabies
can in rare instances convey the disease, but no one has found traces of any toxic agent in the
circulation. We obtained no symptoms by the injection of the - serum of rabbits dying from
rabies into normal rabbits and guinea-pigs, either subcutaneously or intraperitoneally, in amounts
up to 13 cc. The serum of rabbits suffering from rabies has no haemolytic action on the corpuscles.
o f n o r m a l r a b b i t s .
We next tried whether inactivated goat antirabic serum could anchor any substance in fixed
virus rabbit serum, fresh rabbit serum acting as complement and sensitized sheep corpuscles as
indicator, but similar degrees of haemolysis occurred in both the test and the control tubes,
showing that, even if such a substance was present in the fixed virus rabbit serum, its combination
with the goat antirabic amboceptor had less affinity for rabbit serum complement than the
haemolytic serum had.
Using fixed virus goat serum in place of fixed virus rabbit serum and goat antirabic serum as
before, it appeared that the presence of inactivated goat antirabic serum increased the complement
-
ing power of the fixed virus goat serum, which points to the conclusion that fixed virus goat serum
contains some substance in combination with part of its complement and that when this comple
-
ment binding substance comes into contact with goat antirabic serum it finds something in the
latter, presumably the amboceptor, for which it has a greater affinity than it has for the comple
-
ment, which is therefore set free to complete the haemolytic amboceptor.
The factthat a positive indication was obtained when goat antirabic serum and goat fixed
virus serum met, and a negative result when goat antirabic serum and rabbit fixed virus serum met
is in accordance with the established notion that homologous antiserums are more potent than
heterologous.
Further experiments with other and more powerful antirabic serums will have to be made
before it can be held to be certain that any substance is present in the circulation in rabies
capable of being anchored by the amboceptor of an antirabic serum.
(3) Experiments on the same lines as the above were made to ascertain whether any antibody
could be found in the serum of animals actually suffering from rabies, which would combine with
the virus present in the brains of the same animals, normal brain emulsion being the control, but
in neither the rabbit nor the goat did any positive indication occur.
(4) A series of experiments undertaken with another aim in view incidentally demonstrated
that the injection of fixed virus rabbit brains into goats in the process of preparing an antirabic.