INFECTIOUS DISEASES OF CATTLE. 463 



is to be preferred. Burning large carcasses is not always feasible. 

 It is, however, the most certain means of destroying infectious mate- 

 rial of any kind, and should be resorted to whenever practicable and 

 economical. All carcasses, whether buried, rendered, or burned, 

 should be disposed of without being opened. '\Mien stables have 

 become infected they should be thorough!}' cleaned out, and the solu- 

 tion of chlorid of lime freely applied on floors and woodwork. The 

 feed should be carefully protected from contamination with the 

 manure or other discharges from the sick. 



(2) Preventive inoculation. — One of the most important dis- 

 coveries in connection with the disease was made by Louis Pasteur 

 in 1881, and consisted in the new principle of producing immunity 

 by the inoculation of weakened cultures of the bacillus causing the 

 disease. This method has been quite extensively adopted in France, 

 and to some extent in other European countries, and in the United 

 States. The fluid used for inoculation consists of bouillon in which 

 modified anthiax bacilli have multiplied and are present in large 

 numbers. The bacilli have been modified by heat so that they have 

 lost to a certain degree their original virulence. Two vaccines are 

 prepared. The first or weaker, for the first inoculation, is obtained 

 by subjecting the bacilli to the attenuating effects of heat for a longer 

 period of time than is the case with the second, or stronger vaccine, 

 for a second inoculation some 12 days later. 



These vaccines have been used for cattle and sheep. Their power 

 to prevent a subsequent attack of anthrax has been the subject of 

 controversy ever since their use began. The French claim that the 

 vaccines are successful in protecting cattle and sheep, and that the 

 losses from anthrax in France have been much reduced by their per- 

 sistent application. According to other observers there are several 

 difficulties inherent in the practical application of anthrax vaccina- 

 tion. Among these may be mentioned the variable degree of attenua- 

 tion of different tubes of the vaccine and the varying susceptibility 

 of the animals to be inoculated. Xevertheless, the use of this vaccine 

 is increasing, and has reduced the mortality in the affected districts 

 from an average of 10 per cent with sheep, to less than 1 per cent, 

 and from 5 per cent with cattle, to less than one-half of 1 per cent. 



It is very important to call attention to the possibilit}- of dis- 

 tributing anthrax by this method of protective inoculation, since the 

 bacilli themselves are present in the culture liquid. It is true that 

 they have been modified and weakened by the process adopted by 

 Pasteur, but it is not impossible that such modified virus may regain 

 its original vindence after it has been scattered broadcast by the 

 inoculation of large herds. Xo vaccination should, therefore, be 

 permitted in localities free from anthrax. It is also obviously un- 



