316 BOARD OF AGRICULTURE. [Pub. Doc. 



guished clinically from foot and mouth disease, has been traced 

 to vaccine virus. The lesions do not resemble vaccine lesions 

 microscopically, the lymph will not produce vaccine lesions in the 

 rabbit, and the cows which have had the disease are not immune to 

 vaccinia. The lesions correspond microscopically to the descrip- 

 tions of the vesicles of the foot and mouth disease, and there is 

 reason to believe that the process is foot and mouth disease. 



E. E. Tyzzer, 

 Assistmit ill PaUiology, Harvard Medical School. 



While these experiments Avere being carried on it was 

 necessary to have some one present night and day to record 

 the results in detail, to care for the animals and to keep oft" 

 trespassers. The agent of the United States Bureau of Ani- 

 mal Industry in charge of the New England office. Dr. S. E. 

 Bennett, assigned two of his assistants to this work, Drs. 

 U. G. Houck and G. A. Johnson ; while Dr. W. T. White, 

 an asfent of the Cattle Bureau of the State Board of Ao-ricul- 

 ture, was detailed to represent the State. They divided the 

 day into Avatches of eight hours each, taking turns in sleep- 

 ing on the premises. 



At the conclusion of the experiments they made a full and 

 detailed report of their observations to Dr. S. E. Bennett, a 

 copy of which is on file in the office of the Cattle Bureau, 

 together with a copy of a report of Dr. T3 zzer to Dr. Ben- 

 nett ; but for publication at this time it seems better to make 

 use of Dr. Tyzzer's report to the Chief of the Cattle Bureau, 

 Avithout going into the matter at greater length. 



It is perfectly evident, from the results of these experi- 

 ments, that vaccine virus may become contaminated Avith the 

 virus of foot and mouth disease, and convey the latter 

 through the medium of animals used for the production of 

 vaccine virus. This accidental discoA^ery may be the solu- 

 tion of the cause of the original outbreak. 



As nearlj^ as can be ascertained, the first place for foot and 

 mouth disease to make its appearance was upon the premises 

 of the late Owen Clark, in Prattsville, just over the Revere 

 line, either late in July or early in August, li)02. By the 

 latter part of August it had spread to the premises of tAvo or 

 three of his neighbors, and thence Avas carried to A^arious 



