No. 4.] RP:P0RT of cattle bureau. 271 



This is about half as much as was done the previous year, 

 with a much larger percentage of reacting animals. 



One reason why so few herds are tested is that the State 

 does not pay for all reacting animals, but only for those that 

 are rendered, the owner receiving what the butcher will 

 allow for the slightly diseased. This places so much of the 

 burden of expense upon the owner that there is not a great 

 demand for herd tests based upon such onerous conditions. 



There are undoubtedly a large number of owners of herds 

 in Massachusetts who have their cattle tested at their own 

 expense, and who keep their herds clean free of cost to the 

 State ; and there are also a number of farmers whose herds 

 have been cleaned up in previous years from whom no recent 

 complaint has been received, and Avhere disease has not reap- 

 peared. There are, however, not any available figures to be 

 quoted in this connection. 



A practical method of innnunization of cattle to be intro- 

 duced into herds where tuberculosis exists or has existed is 

 also greatly to be desired. Koch, Von Behring and others 

 have done work in this line, and Von Behring claims to have 

 discovered a satisfactory method. So far it has only been 

 applied to calves to be raised in herds where tuberculosis 

 exists. Young calves receive an intravenous injection of a 

 certain quantity of an attenuated human tubercle culture, 

 and in three months a second dose five times the size of the 

 first is given in the same way. It is claimed that calves 

 thus treated are immunized for a considerable period, — two 

 or three years ; whether this immunity lasts for the natural 

 length of the animal's life it is yet too soon to say. This 

 method may in time prove of great value to farmers, espe- 

 cially to breeders of pure-bred stock owning herds in which 

 tuberculosis exists. 



If a similar method can be applied to older cattle about to 

 be introduced into dairy herds where tuberculosis is present, 

 it may prove of great benefit. New purchases, after being 

 tested with tuberculin and found to be free from tuberculosis, 

 can be placed in a quarantine stable and immunized before 

 being introduced into the herd. Such a plan, if it proves 

 practicable, would be of great assistance towards the erad- 

 ication of this disease from herds which depend upon the 



