X I'RESIDENTIAI, ADDHKSS. 



cause this bacillus to grow and multiply outside the animal system 

 altogether, or, as we term it, cultivate the organism in an artiticial 

 medium. Thus, if we take on the point of a sterilised platinum 

 needle the merest trace of blood of an animal just dead of 

 Anthrax, and then introduce the point of the needle into any of 

 the ordinary cultivating media, such as broth, gelatine, agaragar, 

 and blood-serum, or even the surface of a boiled potato, we shall 

 obtain in the course of a few days an abundant growth of the 

 Anthrax bacillus, readily visible to the naked eye and presenting 

 a most characteristic growth. On microscopical examination we 

 lind that tliis peculiar wool-like growth is made up of bacilli held 

 end to end in a delicate filamentous sheath. ]3y continual micro- 

 scopical examination of these filaments we shall notice that a 

 number of extraordinary clianges are brought about; the contents 

 of each individual segment or bacillus in the filament sooner or 

 later become granular ; at a later stage a very minute speck 

 appears in the centre of each rod. These bright, highly refractile 

 bodies are the so-called spores, which, in consecpience of the 

 greater power of resisting destruction, are of such importance in 

 the propagation of this dreaded disease. In the blood of the 

 subject affected, these Anthrax bacilli are not able to form spores, 

 but outside the body they give rise abvmdantly to these indestruc- 

 tible forms, and it is this power of producing spores which 

 renders this organism so dangerous and persistent. Thus, if the 

 carcasses of animals dead of Anthrax are lightly buried or allowed 

 to decay on the surface of the earth, the bacilli form spores in 

 the soil, and healthy animals may thus become infected by 

 taking the spores with tlieii' food when grazing. Again, the skin 

 of aniuuils which have died of Anthrax in some countries, espe- 

 cially Russia, not infre(pu>ntly pass into commerce, and often 

 prove fatal to the tanners and wool-sorters who handle them even 

 long afterwards. To give you some idea how tenacious of life 

 and resistant these minute spores are, and how they retain their 

 virv;lent properties, I have witli me this evening a little bottle 

 containing some silk threads which 1 impregnated with Anthrax 

 spores in INIay, IHHG, nearly twelve years ago. In the first three 

 successive winters in London they stood in a cupboard where the 

 temperature was considei'ably below freezing point for several 

 days, but since that time tlioy Ikiac been kept in n moilerately 



