508 BOARD OF AGRICULTURE. [Pub. Doc. 



both classes of work ; and the Board is to-day in receipt of vol- 

 untary requests in greater numbers than it is able to attend to. 



Tuberculosis. 



As experience ripens, we find that the contagious principle 

 of bovine tuberculosis is fully as strong or stronger than was 

 at first supposed. The reason for this seems to be entirely 

 embraced in the fact that in tuberculin we have a much more 

 perfect diagnostic agent than we have ever had previous to this 

 time ; and the results of investigation show that tuberculosis 

 may be very quickly extended from the diseased animal to 

 other healthy animals with which it may come in contact, but 

 that in a large majority of cases the extension is exceedingly 

 subtle. The animals, although they become affected, do not 

 become sufficiently so to be attractive in their symptomology ; 

 'whereas, with the use of tuberculin it is found that the animals 

 are affected very quickly after exposure, and that the disease 

 is largely disseminated throughout the herd ; that it is received 

 and amplified, by the newly infected, in a very small lesion, 

 situated, more probably, in some of the deeper-seated glandular 

 structures of the body, and then, because of the inherent resist- 

 ing power of the animal, it does not receive a further develop- 

 ment until after the lapse of some time, extending even to 

 years in many cases. 



Prevalence. 



Upon page 28 of our report for last year will be found a 

 statement as to the prevalence of this disease in other countries, 

 gathered from such statistics as the commission was then able 

 to obtain, and a statement that the Board had not been able, up 

 to that time, to gather information sufficient to make any valu- 

 able estimate for determining the amount of such disease in 

 Massachusetts. As the result of the experience of the Board 

 up to that time, however, it was found that 24.58 per cent, of 

 animals reported as suspicious by local inspectors were found 

 to be diseased ; 6.21 per cent, of animals examined at Brighton, 

 Watertown and Somerville, and .9 per cent, of the animals 

 examined on the Island of Nantucket. From all of these 

 figures and such other data as could be gathered, the Board 

 was then of opinion that the amount of disease in the State 



