424 VETEEINAEY HYGIENE 



The Queensland Dip used with this bath consists of 8 lbs. 

 White Arsenic, 4J lbs. Caustic Soda, 2J gallons Stockholm 

 Tar, and 8 lbs. Tallow boiled in 400 gallons of water. 



If spraying instead of dipping be adopted, a mechanical 

 mixture of parafifin and water is employed. Oil-water 

 spraying is generally carried out by a special pump, which 

 delivers a definite proportion of paraffin and water, the two 

 being delivered mixed into the tubing, where by means of 

 a special nozzle they are projected with some force in a 

 finely broken condition. The difficulty in all pumps is to 

 maintain a constant ratio between the oil and water ; 20 per 

 cent, of oil in the mixture is recommended for ticks on 

 cattle, if weaker than this the ticks are not killed, if stronger 

 the skin gets blistered. Paraffin kills ticks quicker than 

 arsenic, but it is more difficult to spray properly than to 

 dip properly. 



Saecoptid^. — Of the several sub-families of Sarcoptidae, 

 the Sarcoptinse or Mange Acari, containing the genera 

 Sarcoptes, Psoroptes, and Symbiotes, are of greatest hy- 

 gienic importance. 



Sarcoptes affects all herbivora; it burrows, and tunnels 

 canals or galleries in the skin, producing a disease which in 

 some animals — for example, the horse — is a most serious 

 and formidable complaint. In the sheep sarcoptic mange 

 is not a dangerous disease, and exclusively affects the face ; 

 in the pig it is the only form of mange affecting this 

 animal, and from both the pig and horse a transient form 

 of the disease is said to be transmissible to man. 



Psoroptes is far less serious. This genus lives on the 

 surface of the skin, and bites but does not burrow, though, 

 as may be imagined from its mode of life, it spreads very 

 rapidly, and produces the common parasitic skin disease of 

 all herbivora. 



Symbiotes does not produce a serious disorder in any 

 animal. Among horses it is mainly confined to the legs of 

 the coarser breeds, and in connection with its eradication it 

 is important to remember that the acarus may live for a 

 long time in litter. 



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