THE MICROBES OF ANIMAL DISEASES. 767 



certain time the action of the air kills it. Pasteur has, however, found 

 an expedient by which to accomplish his purpose. When the culture 

 is shown to be sterile in consequence of the death of the microbe, he 

 takes as the mother-culture of a fresh series of daily cultures the one 

 which was made on the day preceding the death of the first mother- 

 culture. In this way he has obtained an attenuated virus with which 

 to inoculate rabbits, and the same result might undoubtedly be ob- 

 tained in the case of horses. 



There are many other contagious diseases which affect domestic 

 animals, and which are probably due to microbes, such as, for instance, 

 the infectious pneumonia of horned cattle. This w r as probably the first 

 disease in which the protective effects of inoculation were tried, accord- 

 ing to Wilhelm's method. This method consisted in making an incis- 

 ion under the animal's tail with a scalpel dipped 1 in the purulent mucus 

 or blood taken from the lung of a beast which had died of pneumonia ; 

 sometimes the serous discharge from the swelling under the tail of an 

 inoculated animal was used for others. Fever and loss of appetite en- 

 sued, lasting from eight to twenty-five days, but the animal was after- 

 ward safe from further attacks of the disease. Cattle-plague, or con- 

 tagious typhus, is likewise ascribed to the presence of a microbe with 

 which we are as yet imperfectly acquainted. 



Experimental septicaemia is entitled to special mention, since it has 

 too often been confounded with anthrax, and has been unskillf ully pro- 

 duced with the intention of vaccinating animals in accordance with 

 Pasteur's process. This occurs when too long an interval (twenty-four 

 hours) elapses after the death of an animal, before taking from it the 

 blood intended for vaccine cultures. After this date the blood no 

 longer contains Bacillus anthra- 

 cs, which i s succeeded by another \ CV^\ 

 microbe termed Vibrio septicus, ~ \ ' 



differing widely from the an- 

 thrax microbe in form, habit, 

 and character (Fig. 4). Bacillus 

 anthracis is straight and im- 



. . ., . Fig. 4. Septic vibrio, bacillus of malisjnant oedema 

 mobile, while the Septic Vibrio (Koch): a. taken from spleen of Guinea-pig; 6, 

 , t -, ,.-, frcm a mouse's lung. 



is sinuous, curled, and mobile. 



Moreover, it is anaerobic, and does not survive contact with the air, but 

 it thrives in a vacuum or in carbonic acid. Since Bacillus anthracis 

 is, on the other hand, an aerobie, it is clear that the two microbes 

 can not exist simultaneously in the blood or in the same culture-liquid. 

 The inoculation with this fresh microbe is no less fatal ; its action is 

 even more rapid than that of Bacillus anthracis, but the lesions are 

 not the same ; the spleen remains normal, while the liver is discolored. 

 The septic vibrio is only found in minute quantities in the blood, so 

 that it has escaped the notice of many observers. It is, however, found 

 in immense numbers in the muscles, in the serous fluid of the intestines, 



