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THE POPULAR SCIENCE MONTHLY. 



The sickness of barn - door poultry, which is commonly called 

 cholera, is caused by the presence in the blood of a small micrococus 

 or bacterium in the form of the figure 8, differing, therefore, in form 

 from Bacillus anthracis, but also an aerobie. It may be cultivated in 

 chicken-broth, neutralized by potash, while it soon dies in the extract 

 of yeast, which is so well adapted to Bacillus anthracis. The mi- 

 crobe of this disease may also be attenuated by culture, and it may be 

 done more easily than in the case of anthrax, since it is not necessary 

 to raise the temperature, as the bacterium of fowl-cholera does not 

 produce spores under culture. Pasteur has therefore been able to 

 prepare an attenuated virus well adapted to protect fowls from fur- 

 ther attacks of this disease. 



The disease affecting swine, which is called rouget, or swine-fever, 

 in the south of France, has been recently studied by Detmers in the 

 United States, where it is also very prevalent, and by Pasteur in the 

 department of Vaucluse. It is a kind of pneumo-enteritis. These 

 observers consider that the disease is caused by a very slender microbe, 

 formed, like that of fowl-cholera, in the shape of the figure 8, but 

 more minute. Others say that there is a bacillus which was observed 

 by Klein as early as 1878 in swine attacked by this disease. In spite 

 of the apparent contradiction, it is probable that we have only two 

 forms of the same microbe, for the bacillus in Klein's culture at first 



Fig. 3. Swine Fever : section of a lymphatic gland, showing a blood-vessel filled with microbes 



(much enlarged). (Klein.) 



resembles Bacterium termo, in the form of an 8, before it is elongated 

 into rods. Pasteur has succeeded in making cultures of microbes in 

 the figure 8. He has inoculated swine with the attenuated form, after 

 which they have been able to resist the disease, so there is reason to 

 hope that in the near future this new vaccine, containing the attenuated 

 microbe, may become the safeguard of our pig-sties. 



An epidemic which raged in Paris in 1881 was called the typhoid 

 fever of horses, and was fatal to more than fifteen hundred animals 

 belonging to the General Omnibus Company in that city. This dis- 

 ease is also produced by a microbe, with which Pasteur was able to 

 inoculate other animals (rabbits) ; for this purpose he made use of the 

 serous discharge from the horses' nostrils. The inoculated rabbits died 

 with all the symptoms and lesions characteristic of the disease. The 

 attenuation of this microbe by culture is difficult, since at the end of a 



