1921.] 



FOOT-AND-MOUTH DISEASE. 



1005 



the viability of the virus inside or outside the bodies of animals — 

 months or years, and to outbreaks occurring almost simul- 

 taneously in parts of the country very remote from each other — 

 Surrey and Northumberland, for example — which have no pos- 

 sible connection with each other., except perhaps through the still 

 mysterious agency whereby the virus travels long distances and 

 in certain directions, this being apparently the same problem 

 as that of invasion from without the country. 



The above classification of outbreaks may at first sight appear 

 somewhat artificial. It will be apparent that it is not so. how- 

 ever, if due consideration be given to the following facts : — 

 {a) That there is often an excessively long interval of time 



between the outbreaks — months and even years. 

 (b\ That outbreaks may occur almost simultaneously at long 

 distances from each other having no possible ordinary 

 connection (feeding stuffs, men. &c.) with each other. 



(c) That for the last 20 years the policy of immediately 

 slaughtering all affected animals and actual contacts before 

 virus can be freely manufactured by them and disseminated, 

 has been almost exclusively followed, together with com- 

 plete disinfection of infected premises both by chemical 

 agents and prolonged isolation. 



(d) That recurrences after re-stocking formerly infected pre- 

 mises with susceptible animals is practically unknown. 



(e) That the same premises are almost never hit twice, as it 

 were, by invasions after more or less long intervals. 



(/) That the efficacy of the measures outlined in (c) would 

 appear to be proved by (d) and (e\ 



In every outbreak it is customary for the Ministry's Inspectors 

 to collect the fullest information possible regarding articles 

 brought on to the place and their origin. Similarly, the recent 

 movements of animals and human beings connected in any way 

 with the premises are inquired into and recorded. Obviously, 

 however, it is information of the kind in connection with initial 

 outbreaks only which might throw light on the manner of inva- 

 sion, and it is such information which has been utilised for the 

 purposes of this article. 



Whether Disease is communicated by Feeding Stuffs, 

 Packing Materials and Human Beings. — These represent the 

 communications between animals of the farm and the outside 

 world, and it is not unnatural that they should have fallen under 

 a sustained suspicion; The object of the inquiries which have 

 been made over a period of years was to find whether any credible 



B 



