300 DISEASES OF CATTLE, SHEEP, GOATS, ETC. 



ible. It is, however, the most certain means of destroying infectious 

 material of any kind, and should be resorted to whenever prac- 

 ticable and economical. All carcasses, whether buried, rendered, or 

 burned, should be disposed of without being opened. When stables 

 have become infected they should be thoroughly cleaned out, and 

 the solution of chloride of lime freely applied on floors and wood- 

 work. 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 this 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 anthrax 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 twelve days later. 



These vaccines have been used for cattle and sheep. Their 

 power to prevent a subsequent attack of anthrax has been the sub- 

 ject 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 persistent application. According to other observers there are 

 several difficulties inherent in the practical application of anthrax 

 vaccination. Among these may be mentioned the variable degree 

 of attenuation of different tubes of the vaccine and the varying sus- 

 ceptibility of the animals to be inoculated. Nevertheless, the use of 

 this vaccine is increasing and has reduced the mortality in the af- 

 fected 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 possibility of dis- 

 tributing antnrax 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 virulence after it has been scattered broadcast by 

 the inoculation of large herds. No vaccination should therefore be 

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

 safe to have such vaccine injected by a layman; instead, it should be 

 handled only by a competent veterinarian. 



Anthrax is an entirely different disease from blackleg, and 

 therefore blackleg vaccine does not act as a preventive against 

 anthrax. 



