224 : 
HERMANN M. BIGGS. 
one of them—present almost unlimited possibilities in preventive 
medicine, and possess a significance the importance and far-reach¬ 
ing nature of which it is scarcely possible for us to comprehend. 
Pasteur gives in addition an explanation as to the method of 
action of the virus in the living organism. He says: “It is 
possible to give a still further interpretation—an interpretation 
surely very strange at first thought, but which deserves the 
greatest consideration, especially as it is in harmony with certain 
results obtained in the observations of phenomena in the life of 
some other forms of the lower organisms, and especially of sev¬ 
eral of the pathogenic bacteria which give birth in their cultiva- 
tions to a material which has the property of preventing their 
own further development.” 
After referring to the micro-organisms of chicken-cholera, 
typhus in pigs, and the cultivation of Aspergillus niger , he con¬ 
tinues ; a Is it not possible that the rabid virus may be formed of 
two distinct substances, one of which is living and capable of 
multiplication in the nervous system, and the other is non-living, 
having the power, when present in sufficient proportion, of arrest¬ 
ing the development of the first? I have considered experimen¬ 
tally in a previous communication, with all the attention that it 
deserves, this third interpretation of the method of prophylaxis 
of rabies.” 
I cannot conclude this portion of this paper without a refer¬ 
ence to two interesting and important questions that arise in con. 
nection with this method of prophylaxis. The first of these is 
the possibility of transmission of the disease, by animals or the 
human being subjected to these inoculations, to other animals or 
human beings during the process of inoculation, or in any period 
after this time. Pasteur states that he has made no experiments 
or observations upon this point. The second question is as to 
the duration of the refractory condition to rabies after the series 
of inoculations has been completed. This period Pasteur believes 
to be not less than one year, and to be probably considerably 
longer than this, but no careful data upon this point are at pres¬ 
ent at hand. 
What conclusions, now, are to be drawn as to the accuracy 
