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ED. NOCARD. 
ficially, modify it to such an extent that it gives to inoculated 
individuals only a benignant disease, a disease readily cured 
which renders animals refractory to natural infection, always 
fatal to the witnesses, such is the capital work of Pasteur in 
medical science. 
The attenuation of the viruses and vaccination by attenu¬ 
ated viruses has been the greatest biological discovery made for 
centuries. 
You all know the celebrated experiments of Pouilly-le-fort. 
The Agricultural Society had offered to Pasteur to make 
public the proof of the unlikely facts he had announced. It had 
collected 50 sheep from districts where anthrax did not exist. 
Of these 50 Pasteur was to vaccinate 25, the others were to be 
used as witnesses. All the 50 were to be inoculated with the 
same unweakened virus ; the 25 witnesses were to die in 48 
hours, while all of the vaccinated were to remain well. The ex¬ 
periment was carried out and two days after the testing inocula¬ 
tion the 25 witnesses were dead ; none of the vaccinated seemed 
to be sick. 
This is an undeniable demonstration of all that Pasteur had 
advanced. This experiment marks a memorable date in the 
history of microbiology : it is the triumph of the method. Now, 
the proof is made in an incontestible way of the value, theoreti¬ 
cal and practical, of the new science ; unbelievers can no longer 
discuss it; those who were hesitating—and they were legion— 
carried away by universal enthusiasm, have joined the small 
troop of the first hour, and now it is an army. Now we will be 
able to work in peace and to collect all the fruits of victory ; all 
the work prepared by the Master is going to be continued, and 
the gathering of the discoveries he has opened to us will be car¬ 
ried out. * * * Indeed, they are becoming so beneficial that 
they have gone beyond all expectation, and so numerous that 
they can scarcely be counted. 
The work of Pasteur in medical science goes back to 1876— 
not yet 25 years ago. It has provoked such change that it can 
be said that nothing like it has been produced in twenty centu- 
