BUREAU OF ANIMAL INDUSTRY. 79 



unequivocal diagnosis of necrotic stomatitis already made, and tlie 

 well-known presence of that disease in the United States as reported 

 continuously by different branches of the bureau service, and because 

 there had been nothing to indicate the presence of foot-and-mouth 

 disease in the United States since 1909, there was no occasion for the 

 pathological division to question the conclusion of the State veterina- 

 rian and the assistant inspector that it was not foot-and-mouth dis- 

 ease, especially as they had both had experience with this disease 

 during the outbreak of 1908-9. 



The possibilities of diagnosing a disease from a bit of tissue are at 

 best restricted, especially if such tissue does not bear a characteristic 

 relation to the disease with which it is associated. Mixed infection 

 frequently leads to erroneous conclusions, and it has been justly stated 

 that the result of laboratory examination should be considered only 

 as one of the factors in arriving at any correct diagnosis. Without a 

 suspicion of the virus of foot-and-mouth disease being in this coun- 

 try, and with absolute knowledge that both mycotic and necrotic 

 stomatitis had been present during the summer as far east ns South 

 Carolina, as far west as Kansas, and as far south as Tampico, Mexico, 

 where an official from Washington had been investigating the char- 

 acter of the disease for six weeks, it is not surprising that an examina- 

 tion of such atypical specimens of foot-and-mouth disease as pus and 

 scabs admittedly are should reveal various molds and fungi and even 

 the necrosis bacillus, but fail to disclose the tru.e character of the 

 disease. The virus of foot-and-mouth disease being ultramicroscopic 

 and filterable in character, ordinary laboratory procedure would not 

 determine its presence, and the inoculation of the usual laboratory 

 animals is likewise insufficient. 



On September 24 the pathologist of the Michigan live-stock sani- 

 tary commission visited an infected farm near Niles at the request 

 of the owner, and made an examination of the cattle and collected 

 specimens, but without arriving at a diagnosis of foot-and-mouth 

 disease. The State veterinarian and this pathologist on September 

 26 visited the same farm as well as others. With regard to this 

 visit the pathologist is quoted in the annual report of the bacteriolo- 

 gist of the State board of agi^iculture as follows : 



I expressed the belief that the disease was foot-and-mouth disease and sug- 

 gested that he [the State veterinarian] telegraph Washington that we were quite 

 positive of foot-and-mouth disease existing in a number of herds around Niles, 

 Mich., and asking for an investigation by an expert while waiting for the results 

 of a laboratory investigation. He agi-eed with me that we had sufficient evi- 

 dence that foot-and-mouth disease existed in these herds, but suggested that the 

 matter be tixken up with the local office in Detroit instead of directly with the 

 office at Washington. 



The specimens collected by the pathologist were taken to Lansing, 

 and on September 28 he inoculated a calf with this material. By 

 October 1 the oalf showed fever and drooling, followed by erosions 

 in the mouth, but the case was not diagnosed as foot-and-mouth dis- 

 ease, because of the absence of foot lesions. 



Neither these visits nor the results of this inoculation were known 

 to the bureau at Washington until October 10, when a letter was 

 received from the inspector in charge at Detroit as hereinafter stated. 



On October 12 the pathologist connected with the office of the State 

 veterinarian of Indiana received specimens from infected animals 

 and made cultures which, upon microscopic examination, disclosed 



