318 BOARD OF AGRICULTURE. [Pub. Doc. 



the New England Vaccine Company ; as it has been shown 

 by Dr. Tyzzer's investigations that the calves inoculated 

 with a mixed vaccine and foot and mouth disease virus did 

 not show easily recognizable symptoms of foot and mouth 

 disease, yet they were capable of producing it in an unmis- 

 takable form among the cattle with which they were kept. 

 At least, there is no history to show that animals used later 

 at the New England Vaccine Company's establishment for 

 the production of vaccine virus had any disease other than 

 cow-pox. However, it is only fair to state that during Sep- 

 tember some experiments were undertaken at Bussey College, 

 to see if vaccine virus, as put upon the market from the estab- 

 lishment whence Dr. Tyzzer's supply came, could produce 

 foot and mouth disease. Some was procured from the manu- 

 facturer in small sealed capillary glass tubes ready for use, 

 and two calves inoculated on the gums and lips, using a tube 

 for each calf. These calves were kept with two young com^s 

 for a month, but no lesions other than those of cow-pox were 

 observed in any of these animals. 



In the report of the Chief of the Cattle Bureau to the State 

 Board of Agriculture, made in January, 1903 (see page 350 

 of report of secretary of State Board of Agriculture for 

 1902), it is stated that it is a difficult matter to say posi- 

 tively just where the disease came from ; but, as it first ap- 

 peared in Prattsville, a locality in Chelsea, "and, as Chelsea 

 is next to East Boston, where the foreign shipping comes in, 

 it is not unlikely that the infection was brought over on a 

 foreign steamer in hay or in straw used for packing mer- 

 chandise, and in some way was carried to one of the places 

 in this locality, and other herds near by were contaminated." 

 But in view of the fact, as ascertained by Dr. Tyzzer's re- 

 searches, that foot and mouth disease may be conveyed by 

 means of impure vaccine virus, and from the information 

 gained from the proprietor of the New England Vaccine 

 Company, it does not seem unlikely that the source of the 

 oriofinal outbreak may have been due to contaminated vaccine 

 virus used for " control " points at the New England Vaccine 

 Company's establishment, and that the animal thus infected 

 carried it to Owen Clark's, whence it spread. 



