. A text-book of bacteriology, including the etiology and prevention of infective diseases and a short account of yeasts, and moulds, haematazoa, and psorosperms. Bacteriology. ANTHRAX. 197 inoculated a second time witli material (deuxieme vaccin) which has been less weakened. The alnimals are then protected against the most virulent anthrax, but only for a time. From a weakened cultvire, according to Klein, new cultures of virulent bacilh can be started, and a c\ilture that can be used as a vaccine for sheep kills a guinea-pig, and then yields bacilli that are fatal to sheep. The virulence of
. A text-book of bacteriology, including the etiology and prevention of infective diseases and a short account of yeasts, and moulds, haematazoa, and psorosperms. Bacteriology. ANTHRAX. 197 inoculated a second time witli material (deuxieme vaccin) which has been less weakened. The alnimals are then protected against the most virulent anthrax, but only for a time. From a weakened cultvire, according to Klein, new cultures of virulent bacilh can be started, and a c\ilture that can be used as a vaccine for sheep kills a guinea-pig, and then yields bacilli that are fatal to sheep. The virulence of the bacillus is also altered by passing the bacillus through different species of animals. The bacillus of sheep or cattle is fatal when re-inoculated into sheep or cattle; but if inoculated in mice, the bacilli then obtained lose their virulence for sheep or cattle, only a transitory illness results, and the animals are pi'otected for a time against virulent anthrax. Exposure to a temperature of 55° C, or treatment with "5 to 1 per cent, carbolic acid, deprives the bacilli of their virulence. Chauveau obtained a similar result by cultivating the bacillus at 38° or 39° 0. under a pressure of eight atmospheres. The possibility of mitigating the virus depends upon the species of animal; rodents cannot be rendered immune by any known anthrax vaccine. The nature of the toxic products has been described in a previous chapter (p. 42). Methods op Staining the BACiiiLus Antheacis. Cover-glass preparations of blood, etc., can be stained with a watery solution of any of the aniline dyes, or with Neelsen's solution and subsequent treatment with alcohol (p. 87). The preparations may be dried and mounted permanently in Canada balsam, but the typical appearances are best observed in freshly stained specimens examined in water. The sheath and protoplasmic contents can be demonstrated in cover-glass preparations from the blood or spleen which have been stained with eosin after the met
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