'No doubt,' Pasteur answered, 'we have never had in our experimental studies so many animals at our disposition to inoculate; but I have full confidence. What has been already done in my laboratory is to me a guarantee of what can be done.' And M. Bouley, confident also in the assurances of his illustrious friend, and arranging to meet him, to witness these audacious experiments, said to his anxious colleagues, 'Fear nothing; he will come back triumphant.' The experiments began on May 5, 1881, at four kilometers' distance from Melun, in a farm of the commune of Pouilly-le-Fort, belonging to a veterinary doctor, M. Rossignol, secretary-general of the Society of Melun. At the desire of the Society of Agriculture, a goat had been substituted for one of the twenty-five sheep of the first lot. On the 5th of May they inoculated, by means of the little syringe of Pravaz--that which is used in all hypodermic injections--twenty-four sheep, the goat, and six cows with five drops of an attenuated splenic virus. Twelve days after, on May 17, they reinoculated these thirty-one animals with an attenuated virus, which was, however, stronger than the preceding one. On May 31 very virulent inoculation was effected. Veterinary doctors, inquisitive people, and agriculturists formed a crowd round this little flock. The thirty-one vaccinated subjects awaiting the terrible trial stood side by side with the twenty-five sheep and the four cows, which awaited also their first turn of virulent inoculation. Upon the proposal of a veterinary doctor, who disguised his scepticism under the expressed desire to render the trials more comparative, they inoculated alternately a vaccinated and a non-vaccinated animal. A meeting was then arranged by Pasteur and all other persons present for Thursday, June 2, thus allowing an interval of forty-eight hours after the virulent inoculation. More than two hundred persons met that day at Melun. The Prefect of Seine-et-Marne, M. Patinot, senators, general counsellors, journalists, a great number of doctors, of veterinary surgeons, and farmers; those who believed, and those who doubted, came, impatient for the result. On their arrival at the farm of Pouilly-le-Fort, they could not repress a shout of admiration. Out of the twenty-five sheep which had not been vaccinated, twenty-one were dead; the goat was also dead; two other sheep were dying, and the last, already smitten, was certain to die that very evening. The non-vaccinated cows had all voluminous swellings at the point of inoculation, behind the shoulder. The fever was intense, and they had no longer strength to eat. The vaccinated sheep were in full health and gaiety. The vaccinated cows showed no tumour; they had not even suffered an elevation of temperature, and they continued to eat quietly.