15 

 given a reasonable amount of success. It consists in slaughter 

 of tlie advanced cases and the isolation of the reacting animals 

 which show no evidence of the disease, and keeping them for 

 breeding purposes. The calves are separated from their dams 

 immediately after birth, and fed on the milk of healthy cows or 

 the sterilized milk of the reacting ones. Of course, one readily 

 sees that this is not the " perfect way," for there is the element 

 of danger, infection that must exist from all reacting animals 

 tested with tuberculin. 



The method of Prof. Ostertag of Berlin, Germany, a modi- 

 fication of Bang's, demands a clinical examination of the herd 

 and the elimination of animals with open Tuberculosis, since 

 only these excrete the tubercle bacilli, and hence endanger the 

 healthy animals. In a certain sense, Ostertag's method pre- 

 supposes that a clinical examination will discover the really 

 dangerous animals to such a degree that the results will be an 

 efficient way to keep down the tuberculous dissemination. Also 

 he demands a bacterial exa'mination of the milk of a suspected 

 single animal as well as the milk of the entire herd, and also 

 the raising of calves on sterilized milk. Here again is the ele- 

 ment of danger, from infecting the young stock, but no doubt 

 it has a reasonable amount of worth, if due care is exercised. 



In 1901, Prof. Emil von Behring of Marburg, Germany, 

 made known his Bovovaccine, for immunizing calves against 

 Tuberculosis. He has already to his credit the discovery of 

 the antitoxines of diphtheria and tetanus (lockjaw,) the value 

 of which every practicing physician knows. 



Bovovaccine consists of attenuated human tubercle bacilli, 

 in sterilized normal salt solution, retains its vitality from four 

 to five weeks, and is harmless when introduced into cattle. 



Only healthy calves are to be treated ; those out of condi- 

 tion should not be treated until they show good form. No cows 

 in milk are to be bovovaccinated. 



The age for this treatment is between two and twelve weeks, 

 though animals over three months and up to one year of age. 

 that have passed a satisfactory tuberculin test, may be treated. 

 Three or four days should elapse between the tuberculin test 

 and the vaccination with bovovaccine. 



It is best to give a second treatment of the bovovaccine 



