174 G. G. Heslop: 



*charose or lactose. Animal inoculation ultimately establishes 

 the character of the organisms growing in the media. 



Serological Tests. 



In order to obtain a supply of cattle serum for subsequent 

 tests, blood was obtained in sterile bottles from naturally infected 

 animals which were slaughtered at the City and various Metro- 

 politan Abattoirs. In each case the carcase of the animal sup- 

 plying the blood sample was submitted to a post-mortem exam- 

 ination, and lesions of contagious pleuro-pneumonia were demon- 

 strated in the lungs before the blood sample was labelled " posi- 

 tive." Each sample was given a number, and a record kept of 

 .the source of each sample. 



In addition to these samples, which were mainly collected by 

 myself, I am indebted to the officers of the Stock Diseases Branch 

 -of the Victorian Department of Agriculture for several blood 

 samples taken from animals which were killed in the field. No 

 sample was labelled " positive " unless at the time the sample 

 was taken the animal was submitted to a post-mortem examina- 

 tion, and found to be affected with recognisable lesions of pleuro- 

 pneumonia. In this manner it has been possible to obtain a large 

 and representative collection of positive blood samples from 

 several individual outbreaks of pleuro-pneumonia in Victoria. 



Blood samples were also taken from cattle whose previous his- 

 tory could be definitely determined, and who were known not 

 to be affected with pleuro-pneumonia, or to have been in contact 

 with affected animals at any time prior to the taking of the 

 blood sample. In addition to. these " positive " and " negative " 

 blood samples, blood samples were taken from a few animals 

 which had reacted to an inoculation in the tail of virulent serosity 

 taken from the lungs of an infected animal. These inoculated 

 animals were found on slaughter and post-mortem examination 

 not to be affected with any visible lesions of pleuro-pneumonia 

 in the lungs. Samples of blood were taken from time to time 

 from animals which were being kept and used at the Veterinary 

 Research Institute as experimental animals for pleuro-pneumonia 

 and other cattle diseases. In all cases the blood was taken from 

 the jugular vein, and collected into sterile bottles. The blood was 

 allowed to clot, and the serum to separate off from the clot. The 

 serum was then decanted into another sterile bottle, and diluted in 

 «qual parts with 1 per cent, carbolic acid in normal saline solu- 



