PREVENTIVE MEDICINE 291 



are essential for successful combative measures to be applied with 

 as small interference with trade as possible. The premises con- 

 taining the suspected animals must be immediately isolated, and 

 both animals and people prevented from either entering or leaving. 

 Confirmation of the suspicion is followed by slaughter of all animals 

 especially susceptible, that is, cattle, sheep, goats and swine. The 

 slaughtering out of animals which have not been in contact with 

 those not immediately exposed to infection is a matter for decision 

 according to circumstances. Rigid movement restriction orders 

 are enforced within an area having a radius of 15 miles or so from 

 the infected premises. 



Ships, wagons, lairages and saleyards with which infected 

 animals or contact animals have been associated must undergo a 

 strict cleansing and disinfection. 



Stacks of hay located near infected premises may quite well 

 hold the virus, and these may be disinfected by superheated steam 

 as was done by the Irish Department in 1912. Steam was injected 

 from an engine into the ricks to a depth of 1 feet to 2 feet. The 

 heat penetrated to a depth of over 3 feet, and thermometer tests 

 showed a temperature of 220 F. All dung, litter, and loose fodder 

 must be burned. Such persons as have authority to enter infected 

 places must wear rubber overalls and rubber high boots, as such 

 can be readily disinfected. All persons before leaving infected 

 premises may be conveniently rendered free from infection by 

 fumigation with sulphur gas in cubicles erected on the premises. 



Dogs and cats on infected premises should either be locked up 

 or destroyed. The treatment of fields in which infected animals 

 have been is a difficult problem; in Ireland they were freely 

 sprinkled with freshly-burnt lime with the aid of sprinkling 

 machines. Since the virus can remain active outside the body for 

 a considerable but unknown period, it is not easy to say how soon 

 such fields may be re-used for grazing purposes. The policy adopted 

 by the Board of Agriculture during the 1911 outbreaks was to 

 keep pastures free from susceptible animals for at least a month 

 after disinfection. This was found to be a safe period on many 

 occasions. 



Packing material should be burnt after being used. Imported 

 milk should be heated to 60 C. It was advised by the Depart- 

 mental Committee of 1911 that hides and skins, hoofs, bones, &c., 

 should be properly disinfected before being exported, and that a 

 certificate to this effect should be required before the discharge of 

 the cargo. It appeared that in the case of wet hides the inside of the 

 skin should be washed with a solution of per cent, formic acid or 



