15 



dently expected up to the date of its introduction to be able by the 

 weeding-out process, immediate slaughter of suspicious animals, by 

 careful selection, and breeding and good sanitary surroundings to 

 eradicate the disease from the herd. That in all probability we 

 should never have been able to accomplish this is shown by a study 

 of the records of the tuberculin tests. 



The autopsies made upon the thirty-two animals slaughtered in 

 June of liS94 revealed the fact that only seven were free from the 

 disease, and still only two of the whole number were badly affected, 

 and in these the tubercles were in such condition and so situated that 

 the general health of the creatures had not suffered, neither had 

 physical symptoms developed so that by the ordinary examination a 

 diagnosis of tuberculosis could have been made. 



JNIany of the twenty-eight grade animals purchased in October, 

 1890, were slaughtered at this time. Since about the yenr 1890 no 

 animals have been sold from the herd except for immediate slaughter. 

 All carcasses found affected have been disposed of by rendering or 

 deep burial. 



The tuberculin tests were begun in Octobei-, 1892, and concluded 

 in June, 1894. During that time numerous injections were made 

 upon animals in the college herd. In all cases the animals have been 

 slaughtered and in every instance a careful post-mortem examination 

 made to determine the presence of tubercles. In some of the cases 

 but not all, when it was doubtful whether tuberculosis existed, 

 parts have been examined microscopically to make if possible a 

 correct diagnosis. With those animals that were pronounced 

 sound after having given a reaction it was not possible to discover 

 tubercles after a careful search at the time of slaughter. In some 

 no part of the tissues was submitted to microscopical examination 

 for it was impossible to find anything that presented a single charac- 

 ter of a tubercular lesion. That they may have been present we 

 cannot absolutely deny, but can say after a most searching examina- 

 tion that we were unable to find anything resembling a tubercle to 

 submit to examination. 



The tuberculin used in the tests was Koch's tuberculin (Tubercu- 

 linum Kochii) imported from Germany. 



Before injection it was diluted, 1 c. c. of tuberculin being mixed 

 with 9 c. c. of 1 % carbolic acid solution made with distilled water. 



Previous lo its use the temperature of the animal was taken on 

 one or several occasions, by means of a fever thermometer inserted 

 into the rectum, the last reading being taken immediately before the 



