228 
Rabies 
that the virus remained fixed for the dog, but in the 5th passage, the 
animal did not show rabies, that is to say complete failure to infect had 
occurred. But when this same dog was reinoculated 20 days later 
from the glycerine preserved brain of passage dog 4, it contracted 
dumb rabies after the fixed virus incubation period, thus showing 
that the loss of the virus was not due to attenuation, but to technique. 
TABLE I. Showing the passage o f fixed virus in the dog. 
No. of 
Wt. of dog 
Incubation 
Cultures 
Type of 
passage 
in grammes 
period: death 
from brain 
rabies 
1st 
10,000 
8/10 
Negative 
Paralytic 
2nd 
11,060 
6/7 
5 ) 
5 ? 
3rd 
11,-500 
7/9 
)> 
» J 
4th 
10,640 
7/10 
) ) 
? J 
5 th 
8,350 
a, Escaped to 
a, Escaped rabies 
subdural 
inoculation 
h, Eeinoculated h. Negative 6, Paralytic rabies 
8/11 
Escape to the subdural test has been largely taken by writers on 
the subject of rabies immunization to be synonymous with immunity in 
the test animals. In a memoir which is in preparation we shall deal 
with this subject at length, and show how faulty technique, refluxes of 
the virus, and contact with antiseptics are all factors which contribute 
to escapes. Therefore we hold that in all experimental work on rabies 
the controls should be equal in every respect {i.e. in number, size etc.) to 
the test animals. We regard many of the contrary opinions explicable 
simply on the grounds of faulty technique and consider that this error 
would be eliminated if proper attention were paid to controls. 
At the International Congress at Copenhagen, Pasteur (1884) 
stated that “ On the 6th of December 1883, the medulla of a rabid dog, 
in which rabies had been induced by the inoculation of the virus of 
a child dead of rabies, was inoculated into a monkey by trephining. The 
monkey developed rabies eleven days later; from this first monkey an 
inoculation was made into a second, which still took rabies on the 
11th day. In a third monkey rabies did not show until the 23rd day, 
etc. The medulla of each of these monkeys was inoculated by tre¬ 
phining into two rabbits for each passage. The rabbits inoculated 
from the first monkey took rabies on the thirteenth and sixteenth day, 
respectively ; those from the fourth on the 28th day; those from the 
fifth on the 27th day ; those from the sixth on the 30th day.” Pasteur 
did not state the species of monkey used. 
