No. 4.] REPORT OF CATTLE BUREAU. 133 



swine, slicep and oilier ruiuinaiits, liay, grain, straw. Lags, 

 hides, lioofs, etc., from these States were finally revoked. It 

 was fonnd that the disease was started in ^Michigan by young 

 eattle that had been used by a large drug-manufacturing estab- 

 lishment for the production of vaccine virus, and that the con- 

 taminated virus used there came from another establishment 

 in Philadel])hia. It was from this Philadelphia firm that the 

 vaccine virus came that produced the foot-and-mouth disease 

 at Wakcheld in the summer of 1903, when Dr. Tyzzer was 

 making his investigations on vaccine. It was from the Phila- 

 delphia establishment also that the vaccine virus used as a 

 control seed by the New England Vaccine Company, in CUiel- 

 sea, was obtained in the summer of 190:2 ; and it was at Owen 

 Clark's place in Chelsea that foot-and-mouth disease seems 

 first to have started in 1902, he being the man who supplied 

 cattle to the New England Vaccine Company, and who took 

 them away again after the company was through with them. 

 The reason why the disease never escaped in the vicinity of 

 Philadelphia seems to be that the calves used there were killed 

 and autopsies made upon them after the vaccine virus was 

 taken from them, instead of being sold to farmers, as is the 

 custom in some establishments. The outbreak of 1908-09 in 

 Michigan, New York and Pennsylvania seems, therefore, to 

 have come from the same source as the Massachusetts outbreak 

 in 1902-03, and to have been carried along in the vaccine 

 virus of the Philadelphia manufacturer for a number of years. 



The United States Marine Hospital Service has control of 

 the production of vaccine virus in the United States, and it 

 has now traced out all the contaminated vaccine virus and de- 

 stroyed it; therefore, there seems to be no further danger of 

 any more outbreaks of foot-and-mouth disease from this 

 source, — outbreaks that have cost the country several millions 

 of dollars. 



It is said that none of the contaminated virus from the De- 

 troit establishment was ever put upon the market, as all that 

 was produced from the seed obtained from the Philadelphia 

 firm was set aside, and none of it had ever been sent out at 

 the time it was ascertained that it was contaminated and ought 

 to be destroyed. 



