QQS Seventeenth Annual Report of the 



quarantine station, thus infecting two work oxen that followed 

 over the road the same day. All were rigidly isolated and the 

 spread of the malady was stopped. 



A serious outbreak occurring in the vicinity of the docks at 

 Chelsea, Massachusetts, in the middle of November, 1902, was 

 recognized by the state and federal officials. By examination of 

 practicing veterinarians, dairymen and dealers, I secured good 

 circumstantial evidence that the disease had existed as early as 

 June (five months before), and the smoldering and spreading of 

 the infection for that length of time had doubtless laid a founda- 

 tion for the remarkable intractibility which helped to keep the 

 outbreak in existence for several more months — until May, 1903. 

 This outbreak also presented a more severe type than that of 1870. 

 The campaign for its extinction had to be carried on in four 

 states — Massachusetts, Vermont, New Hampshire and Rhode 

 Island. The most vigorous repressive measures were resorted to, 

 including the prompt slaughter of every herd known to be infected 

 and the disinfection of the premises. The work was finally 

 crowned by a complete success. 



The real origin of this New England outbreak has not been 

 definitely ascertained. Among the most plausible theories ad- 

 vanced are these: 



1. The landing of European hay or straw along with imported 

 horses, cattle, sheep, or swine, or with menagerie animals which 

 were not subject to quarantine. 



2. The bringing ashore of halters, ropes, blankets, hoods, cir- 

 cingles, harness, etc., which had been used on infected animals. 



?>. The escape of infected hay or straw used in the packing of 

 crockery, glass, or other imported goods. 



4. Importation of fresh infected wool, hair, bristles, hoofs, 

 horns, or hides. 



5. The importation of vaccine virus or other alleged laboratory, 

 therapeutic or preventive serum or other preparation which had 

 been contaminated with the microbe of foot and mouth disease. 

 An accident which happened during the progress of the Massachu- 

 setts outbreak is quite suggestive in this connection. Dr. Tizzer 

 vaccinated a calf on his father's farm with cowpox lymph taken 

 from a package which bore Japanese labels, Japan being a foot 



