CONTAGIOUS DISEASES-NEW DISCOVERIES. 
403 
small-pox. If, then, to Jenner we owe the grand process of 
vaccination against small-pox, to Pasteur, Arloing and their co¬ 
workers we owe the vaccination of both species of anthrax, as 
well as the bacteridian as the bacterian form. 
The time is too short for me to recall to your mind all the 
writings that have been published on these subjects, or to detail 
the successful experiments that have been reported, as well as the 
failures that were against them. It is now an admitted fact 
throughout the world, and demonstrated in every portion of the 
continent of Europe by hundreds of thousands of living witnesses 
in the forms of the animals whose lives it has saved, that vacci¬ 
nation, if we may use that word, is the grandest thing resulting 
from these modern discoveries. I use the word vaccination, as, to 
quote the expression of Pasteur and Bouley, it is a true vaccina¬ 
tion. It is the introduction of the modified virus, of the attenu¬ 
ated virulent element, which is just changed into vaccine by the 
peculiar manipulations of the laboratory, which though they 
diminish the strength of the virus, do not remove its entire 
vitality, since when placed in favorable circumstances, it is likely 
to return to its former condition and become as dangerous as be¬ 
fore. 
As the two forms of anthrax are quite common in various 
parts of this country, and satisfied, as I am, of the benefit to be 
derived by vaccination, I thought it might be of interest to pres¬ 
ent this meeting with the material used, as well as to say a few 
words on their application, it being understood, however, that in 
relating the process of application, I have no wish to ignore other 
methods, but present these as being considered by me, at present, 
as most practicable, and with the hope that some amongst ns will 
be pleased to try them either as a mere experiment or in actual 
practice. 
The process inaugurated by Pasteur is based upon this princi¬ 
pal :—that when an animal has suffered from a mild attack of 
anthrax, he is protected at least for a certain time by an acquired 
immunity, and has become refractory—and if the attack of the 
disease is produced by the introduction under the skin of bacteri- 
dies, ttenuated in heir virulency, the subject is also protected, 
