"BRAXY" sheep disease in AUSTRALIA. 571 



Age and Condition Incidence. — It is confined almost entirely to 

 young sheep, four to six-tooth (2 to 2 J years), especially those in 

 good condition, and affects equally male and female. 



Symptoms. — Seldom are any evidences of sickness observed ; 

 at most some dulness and disinclination to move may be detected, 

 but this is rare. That the disease must be very rapid in its course 

 I had personal evidence. The evening of my arrival 700 wethers 

 bad been mustered into a small paddock near the homestead for 

 my examination the following morning. No evidence of sickness 

 in any individual, not even a tendency of any particular sheep 

 to lag behind, was noticed by the shepherd. Yet the following 

 morning at daybreak two were found dead with rigor mortis well 

 advanced and the bodies tympanitic and almost cold. That same 

 evening I watched the sheep carefully as they were mustered in 

 the larger paddock and driven into the smaller, but could detect 

 absolutely no indication of sickness in any. Twelve hours later 

 one was found dead and cold, the night having been cold and 

 frosty. Death occurs quietly, there never being any evidence of 

 struggling. 



Post-mortem Appearances. — The carcase is always that of a very 

 well nourished young sheep. Development of gas within the 

 stomach and bowels occurs rapidly. Patches of gelatinous sub- 

 cutaneous oedema, slightly blood-tinged, particularly about the 

 thorax and abdomen, are very noticeable on removal of the skin. 

 The peritoneal and pleural cavities contain a variable quantity of 

 blood-tinged watery effusion, and the pericardium is often greatly 

 distended with clear semi-gelatinous exudate, a feature especially 

 noticed by the owner in many cases. There may be acute peri- 

 tonitis, with slight formation of false membranes, but this is far 

 from constant, being observed by me in only one case. The 

 stomach is always more or less deeply congested, but I have 

 observed no ulceration. The liver often presents a mottled appear- 

 ance due to circumscribed irregular areas of necrosis. The spleen 

 is somewhat enlarged and softer than normal. The kidneys are 

 congested. The lungs are usually firmer than normal, due to 

 cedematous infiltration. The heart may show sub-endocardial 

 haemorrhages. The lymphatic glands are more or less cedematous, 

 and many may be very haemorrhagic. Provided the post-mortem 

 examination be made soon after death in cold weather no very 

 definite odour of putrefaction is to be detected, although as a rule 

 when dead sheep are found decomposition is advanced. (See 

 Appendix BI.) 



The Pathogenic Organism. 



The bacilli isolated, although, as will be seen later, presenting 

 certain differences, are in their main features so alike that for con- 

 venience and brevity they can be described as one. 



