" BRAXY " SHEEP DISEASE IN AUSTRALIA. 575 



other, the plane probably depending upon that of the first bacillus 

 on coming to rest in the medium. (See photograph). Gas forma- 

 tion occurs, but the medium is not completely shattered as with 

 many other anaerobic gas-producing bacilli. 



In glucose gelatine at 22° C. separate colonies appear in 48 

 hours after inoculation. These colonies are less definitely disc 

 shaped, and are composed of a central dark mass with a clearer 

 zone. No definite hquefaction is seen until the eighth day at least, 

 and there is little gas formation. The colonies, unlike those in agar, 

 appear to continue to grow, although this is probably due to the 

 progressive liquefaction of the surrounding medium. 



Spondation. — The bacilli sporulate very readily within the 

 tissues, especially within the blood infiltrated muscle. In the 

 cedemas, before death at all events, there is little tendency to form, 

 spores, evidently owing to the facility for reproduction. In cedema, 

 blood, etc., witliin pipettes at 37° C sporulation is rapid. In serum 

 broth sporulation is definite and spores are numerous. In glucose 

 media, even with serum, however, they are rare, often entirely 

 absent so far as microscopical examination can detect. In glucose 

 agar especially I have failed to observe any attempt to form spores. 

 The spores are ovoid and generally terminal or situated close to one- 

 extremity. 



Odour of Gas Produced by Bacilli. — Provided a cadaver is 

 examined soon after death often no definite gas formation and no 

 definite odour can be detected. Frequently the odor is what may 

 be described as an aggravated " muttony " or " sheepy " smelL 

 The quantity of the gas and the odour seem to depend greatly on 

 the extent to which the muscles are invaded by the bacilli, which 

 generally in experimental animals depends on how deep the needle 

 has penetrated. In any case where post-mortem examination is 

 made early if a slight putrefactive odour be present it rapidly dis- 

 appears on removal of the skin. 



In muscle (eerobic) cultures the odour, especially of the Tas- 

 manian bacillus, is definitely " cheesy " ; in anaerobic cultures 

 under oil, especially again with the Tasmanian bacillus, it is definitely 

 more that of stale urine. These observations have been repeatedly 

 confirmed, and refer to cultures in tubes. When in bulk of 50 to 

 100 cc. the odour is rather a mixture of a cheesy and peculiar 

 putrefactive odours indescribable, and can be detected with both 

 bacilli. 



No odour is detected in agar cultures. 



Virulence of Cultures. — In ordinary serum broth the virulence 

 is retained to a very great extent, even though successive sub- 

 cultures. In glucose media, however, the virulence rapidly de- 

 creases, so much so that within a week an orginally virulent and very 

 fatal culture wiU prove innocuous, even in large doses, although 

 they are capable of conferring a definite immunity, as will be shown 



