No. 6. DEPARTMENT OF AGRICULTURE. 139 



Stah' Live Stock Suuilai'v Board so stronj^ly dial a r<(inest was 

 made to the las( Lej;islaliu*e lor an addition to the usual appro- 

 priation for kiboratory and research work, so that a farm niij.'lit 

 be rented and a herd of cattle established for experimental i)ur- 

 poses, with the view of testing- and, if possible, of developing the 

 principle and practice of vaccination against tuberculosis as ap- 

 plied to cattle. It was hoped that by this means it might be pos- 

 sible to develop this mode of protection to a point where it could 

 be made of practical value to cattle owners. With this "object in 

 view a farm has been rented in Delaware county, within easy reach 

 of the laboratory of the State Live Stock Sanitary Board, and a 

 herd of cattle has been established. It has been necessary to pro- 

 vide some special equipment in the way of laboratory and stable 

 accommodations. 



The experiment consists in vaccinating 3'oung cattle with vaccine 

 of diiferent kinds, with doses of different sizes and at varying inter- 

 vals. Each mode of vaccination is tried upon a group of from two 

 to four animals. Along with animals that are vaccinated there 

 are a number of similar aniinals that have not been vaccinated 

 and that are kept as check or control animals. The vaccinated and 

 unvacciuated animals are exposed to immediate, direct, daily con- 

 tact with cows aftlicted with tuberculosis. The purpose of this trial, 

 as will be seen, is to determine whether and, if so, to what extent, 

 the different modes of vaccination are effective as compared with 

 the conditions found in unvacciuated animals equally exposed. 

 Trial is also being made as to the elficiency of vaccination in 

 the protection of calves from tubercular cows that are reared 

 upon the milk of their diseased mothers and are in constant contact 

 with them. 



The principle of immunization of animals against tuberculosis 

 having been proven, information is now particularly desired upon 

 two points, first, as to the most effective and economical method 

 of applying vaccination, with respect chiefly to the number of times 

 that the process shall be repeated, and, second, as to the duration 

 of the immunity that is thus conferred. It will be seen that in- 

 formation of this kind can not be obtained quickly, but it is be- 

 lieved that the object sought is of importance enough to justify 

 a continuance of the experiment on an adequate scale. The final 

 results are not reached and a definite report upon the work cannot 

 be made until the animals under observation have been killed and 

 careful postmortem examinations are made. However, so far as 

 one can judge of the work in its present incomplete state, it is 

 promising and encourages the belief that vaccination against tu 

 herculosis may be placed upon a practical footing. 



Vei'minous Bronchitis of Calves. — The common lung worm 



