■" BRAXY " SHEEP DISEASE IN AUSTRALIA. 599 



method has been entirely abandoned in Great Britain. Al- 

 though I have actually demonstrated that at any time 

 definite immunity can be produced by drenching with virulent 

 cultures, one would hesitate, at least at present, to recom- 

 mend the adoption of such a method on a large scale, 

 especially in view of Hamilton's statement that he found 

 the braxy bacilli thus introduced being still expelled by the 

 faeces two months later. If an unburned and unburied carcase of 

 an animal dead of the disease is, as admitted by Hamilton in 

 •common with others, a certain source of contamination of the 

 surrounding soil, and even at some distance by water, etc., sheep 

 continuously passing quantities of the pathogenic germs are more 

 likely to be spreaders of future infection ; and indeed, in view of 

 the frequent moving of sheep over a country, to become definite 

 carriers of infection to hitherto clean farms. Disease carriers, them- 

 selves immune, are well known to exist with other maladies. 



As I have shown, it is possible to immunize sheep to experi- 

 mental injection by means of weakened cultures, but whether 

 this method would prove satisfactory from the economic and 

 practical view point is another matter. So far no opportunity has 

 presented itself of testing this method, the reason being apparent 

 later. That it would be efficacious from the scientific standpoint 

 is to be anticipated from the experiments and from the success 

 attendant on blackleg vaccination. 



With sheep diseases, however, in view of the small value 

 relatively of each animal, the large numbers to be treated, it is 

 always advisable to seek for the most practical measures in the 

 prevention of disease, bearing in mind that an annual mortality 

 of even two per cent, is generally viewed with great equanimity 

 by the flockowner. An example of such a measure is afforded 

 "by the success of my recommendations for the prevention of the 

 New Zealand hogget disease. These recommendations shortly 

 were as follow : — ■ 



1. Destruction by fire or burial of all carcases, and 

 (2) the provision of dry food, as straw, hay, etc., or, prefer- 

 ably, a " run-off " to rough herbage. 



The result has been that the disease has almost disappeared. 



In Tasmania the recommendation was made that on the 

 approach of the dangerous period of the year the young sheep 

 should be removed for two or three months from the affected 

 areas, and the ewes, which are rarely if ever attacked, placed 

 thereon ; in other words, I considered some system of manage- 

 ment should overcome the mortality to a very great extent. 

 Whether this has been attempted, or if not, why it has not been 

 tried, I have not been advised. 



On the Victorian farm where the outbreak detailed occurred 

 I recommended the drainage of the small swampy areas and their 

 cultivation, where possible, around the springs, the collection oi 

 the drinking water from the springs in troughs, in order to abolish 



