FOOT-AND-MOUTH DISEASE. 301 



pyogMie>. and not as the eontagium of the disease. The author has 

 pointed out the variation which exists in the size of the chains and 

 of the colonies, and the difference which is found in tin- rate of 

 growth of cultures of Streptococcus pyogenes. mid these variations are 

 especially marked in Streptococcus pyogenes ho\i>. Klein believe-* 

 that tlie administrations of broth cultures produced the disease in 

 sheep, hut the results were very probably due to accidental infection. 

 It is well known how very readily foot-and-mouth disease is spread. 

 The appearance of a ca>e in a Hock of sheep or a herd of cattle will 

 !> almost certain to be followed by all or nearly all of the other 

 animals being infected with great rapidity. The virus chugs to the 

 clothe-: of shepherds and others who have been in contact with 

 infected sheep, and may be readily conveyed to healthy animals bv 

 tli<e who have l>eeii visiting infected premi>e>. 



Schottelius described chain- composed of rounded element.-, xmie 

 of which resembled an amoeba or plasmodium. The chains were said 

 to be motile, and delicate growths were obtained in blood serum and 

 a gai-. and in broth and on potato. Inoculation in sheep and pigs 

 and numerous small animals gave negative results. These organisms 

 were described as >treptocytes. tn distinguish them from bacteria. 



Piani and Fiorentini investigated the contents of the veside>. and 

 also described corpuscular elements exhibiting auia-boid movements. 

 They regarded these bodies as protoxoa, and concluded that foot-and- 

 mouth disease is due to their presence. 



I'ntil a micro-organism is cultivated which will produce .sheep- 

 pox in sheep on a farm or on premises where the disease does not 

 exist, and where there can be no possibility of accidental infectio 

 we are fully justified in concluding that the nature of the contagiti 

 of this disease is unknown. 



Stamping-OUt System. Foot-and-mouth disease was impcr 

 into this country in 1839. It has been successfully dealt with by the 

 stamping-out system, which in this case is very difficult to apply 

 because of the very short period of incubation, and the value of 

 the stamping-out method very greatly depends upon the length 

 of the incubation periml. Foot-and-mouth disease very often, 

 from infection to recovery, does not exceed ten days; yet according 

 to the reports of the Board of Agriculture, when foot-and-mouth 

 di-ase exi>ts in a manageable state, perfect isolation and effectual 

 disinfection have proved equal to the complete control of the 

 spreading of the infection, and the final extinction of the dis. 

 Nothing more is nec.-ss.-n-y in any case than to clo>e up all the 

 channels through which infected matter can be conveyed; but in 



