9
Goat 4—Weight 26 kilos.—Received 10 cc. of 1 in. 10 fixed virus subcutaneously daily for 10
days, 10 grammes brain substance, 1/2,600 of its body weight.
25 days after the end 50 serum did not destroy 1 virus.
45
75
1
Though this animal received a larger quantity of virus it did not produce as good a serum
as Goat C did after the latter's first series of injections. It succumbed to subdural inoculation
with fixed virus performed 45 days after the end of its treatment.
Horse A—First series of inoculations.—Received subcutaneously 32 . 7 grammes fresh fixed
virus subcutaneously between February 15th—June 7th, 1908.
26 days later 50 serum did not destro y 1 virus.
)
26
200
did
1
Second series of inoculations.—August 12th-23rd, 1908, 12 grammes fresh fixed. virus.
18 days later 80 serum did not destroy 1 virus.
Third series of inoculations.—September 25th—October 10th, 1908, 19 . 1 grammes fresh fixed
virus.
28 days later 20 serum did not destroy 1 virus.
Rabbit 68—Weight 1,280 grammes.—Received 2 cc. 1 in 50 fixed virus subcutaneously daily
for 10 days, 4 grammes substance, 1/3,200 of its body weight.
21 days after the end 95 serum did not destroy 1 virus.
It then received 2 cc. 1 in 10 fixed virus subcutaneously for 10 days, 2 grammes brain sub-
stance, and, as its weight was now 1,400 grammes, 1/700 of its body weight . . . . In all i t
received in 50 days 2 . 4 grammes, about 1/600 of its body weight.
24 days after the end of the course 100 serum did not destroy 1 virus.
This rabbit succumbed to subdural inoculation with fixed virus performed 45 days after the
end of its treatment.
Guinea-pig 59—Weight 490 grammes.—Received increasing doses of fixed virus emulsion`.
subcutaneously during 17 days, in all '34 gramme, 1/1,400 of its body weight.
This pig showed symptoms of rabies 5 days after the end of the treatment and succumbed.
Consideration of the above experiments shows that it is by no means a simple matter to
obtain from animals an antirabic serum capable of destroying fixed virus in vitro in reasonable
proportions. Doubtless individuals vary in this respect just as much in the case of rabies as,
other animals are known to vary in their power of producing potent antitoxic serums(
Remlinger (3) only obtained a serum potent 100 to 1 after the injection of from 120 to 160
grammes of fixed virus brains into wethers.
Marie (4) reports the preparation of an antirabic serum potent 2 .5 to 1 by injecting sheep
with 100 .to 225 grammes fixed virus brains.
Again, Remlinger (5) states that the activity of a serum bears no relation to the quantity
of virus used to immunise the animal, and instances that a sheep which had received about 520
grammes brain substance in 2 years furnished a less active serum than one which had received
only about 324 grammes.
Tizzoni immunised sheep by injecting subcutaneously 25 gramme per kilo daily (17 in-
j ections in 20 days) of virus attenuated with gastric juice, and claimed that he obtained a serum
which protected in doses of 1/25,000 of the body weight !
IMMUNISATION WITH PRESERVED VIRUS.
Most authors state that immunity cannot be produced in animals by the subcutaneous
injection of fixed virus, the virulence off which has been destroyed by drying, heat or chemical
agents (6), but others have claimed to have procured an efficient vaccine by preserving fixed
virus in carbolic acid.
The practical advantages of a vaccine thus preserved are great, for it might be prepared in
a central laboratory and distributed for use to hospitals and practitioners as required, obviating
the necessity of having to travel, perhaps great distances, to a Pasteur Institute for treatment,.
as must be done at present by persons bitten.
Such a vaccine could also be used on animals which had been bitten.
With this end in view we have made some experiments with fixed virus brains emulsified in.
cyllin. It was found that 1 in 300 cyllin sufficed to preserve 1 in 30 brain substance indefinitely
at room temperature, 15° C to 22° C.
Preliminary experiments with rabbits showed that subcutaneous injections of cyllin alone
in the above dilution are well borne, but that no serum immunity against fixed virus was thereby
produced.
3