DEPARTMENT OF AGRICULTURE, 



NEW SOUTH WALES. 



SCIENCE BULLETIN, No. 21. 



The Cause of Black Disease and its Method 



of Transmission.* 



Being Further Studies in a Braxy-like Disease of Sheep. 



IN a previous article f on black disease in sheep in New South Wales, the 

 writer described the history, symptoms, &c., of this condition, and detailed 

 investigations he had carried out regarding its cause. During this research 

 no positive results such as would justify a careful worker in drawing any 

 definite conclusions, were arrived at, and no definite opinion was expressed 

 as to the cause, although three possible causal factors were discussed, via., 

 bacterial, nutritional, and plant poisoning. Reasons were given for rejecting 

 the two latter hypotheses. The probable bacterial origin was discussed, and 

 it was stated that the morbid anatomy of the disease indicated a toxaemia, 

 although at that period no bacteria to account for the condition had been 

 demonstrated with sufficient constancy in the tissues, &c., of animals dead 

 from the disease, provided the precaution had been taken to remove such 

 materials immediately after death to reduce the probabilities of agonai 

 invasion to a minimum, and to completely avoid post-mortem invasion. It 

 was also suggested that it was quite possible that the cause was bacteria 

 which were confined to lesions somewhere, or to the intestines, where a toxin 

 was elaborated. Furthermore, it was demonstrated that when exudates, heart 

 blood, portions of organs, &c., taken at random, were removed immediately 

 after death, no bacteria., with certain exceptions, could be cultivated from them. 

 In the earlier studies, mentioned above, a description of the post-mortem 

 appearance of sheep dead of black disease was given, but this was compiled 

 from autopsies made on animals, many of which had been dead an unknown 



* The matter comprising this bulletin has been written some time, but owing to various 

 circumstances a full description of the cultural and other characteristics of the causal 

 organism has not yet been completed. Some of the former are described herein, but 

 these relate mainly to growth in liquid media. It is fully realised that in view of the 

 recent advance in our knowledge of the biology of the anaerobes, no description of an 

 anaerobic organism can be considered complete unless the cultures are started from a 

 single colony, in order to avoid the possibility that one may be dealing with mixed 

 cultures. The writer had determined to withhold publication until this had been done, 

 but circumstances have arisen which render it desirable that the results of six years 7 

 research in black disease be made known without any further delay. A complete 

 description of the cultural characteristics of the causal organism, and some notes OB 

 serum reactions, &c., can be furnished subsequently. The present matter also appears 

 in the Journal of Comparative Pathology and Therapeutics. 



t Studies in " Black Disease," Agricultural Gazette of New South Wale*, vol. xxix 

 page 657. 



