860 president's address. 



For several years past, although recently exaggerated in extent, 

 there has existed a malady among cattle and horses, principally 

 in the Upper Hunter and Bathurst districts, caused by the 

 ravages of a minute parasitical insect, and which, when micro- 

 scopically examined, will, in my opinion, be found to be a species 

 of that odious family the Holetra of Hermann, and nearly allied 

 to that portion of the genus Acarns which in other countries live 

 on the shin or in the flesh of various animals, and reduce them 

 to a state of great debility. I lay this important matter before 

 your notice in order that some of our resident microscopists may 

 be induced to institute an investigation into the true nature of 

 the evil, and thereby be in a position to point out an effective 

 remedial measure, so as to check the further spread of the disease. 

 These parasites appear to attack only those animals depastured 

 on clover, lucerne, or other introduced food, and to infest 

 exclusively those parts where the hair is white, either in its 

 natural state or arising from spur-marks, abrasions of the saddle, 

 brands, or other wounds. Thus the stock, whose bodies are wholly 

 or partially white, or those with white faces and legs, or with a 

 star on the forehead, suffer only on those places where that colour 

 exists, the skin in such parts being commonly of a pinkish colour 

 and of a more tender texture. These insects in innumerable 

 numbers are probably bred under the skin and burrow into the 

 flesh, inflicting so much irritation that the hair can be peeled off 

 in large masses, leaving the skin underneath as if scalded. The 

 popular belief in the country districts is that these scalded-like 

 patches are caused by the aphis on the pasture. The mischief 

 thus arising has caused the death of many valuable animals, 

 while others have been rendered lame ; but the majority, by 

 constant pain and irritation, have been thrown out of condition, 

 and consequently wholly unfit for the market. Until this last 

 year this pest has been confined to horses and cattle, but I now 

 learn that in the Bathurst district sheep have been attacked, and 

 many have suffered severely. After shearing, where the wool is 



