FOOT-AND-MOUTH DISEASE. 301 



pyogenes, and not as the contagium 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 the rate of 

 growth of cultures of Streptococcus pyogenes, and these variations are 

 especially marked in Streptococcus pyogenes bovis. Klein believes 

 that the administrations of broth cultures produced the disease in 

 sheep, but 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 case in a flock of sheep or a herd of cattle will 

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

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

 clothes of shepherds and others who have been in ^contact with 

 infected sheep,' and may be readily conveyed to healthy animals by 

 those who have been visiting infected premises. 



SchotteUus described chains composed of rounded elements, some 

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

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

 agar, and in broth and on potato. Inoculation in sheep and pigs 

 and numerovis small animals gave negative results. These organisms 

 were described as streptocytes, to distinguish them from bacteria. 



Piani and Fiorentini investigated the contents of the vesicles, and 

 also described coi'puscular elements exhibiting amoeboid movements. 

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

 mouth disease is due to their presence. 



Until 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 possibiHty of accidental infection, 

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

 of this disease is unknown. 



Stamping-out System. — Foot-and-mouth disease was imported 

 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 period. 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 

 disease exists 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 disease. 

 Nothing more is necessary in any case than to close up all the 

 channels through which infected matter can be conveyed ; but in 



