194 SPECIAL BACTERIOLOGY 



later ; the day before they die they sit motionless in one place, their 

 eyes being firmly closed with secretion, and their heads retracted as if 

 they were sleeping, and in this position they die. Animals can also be 

 infected by feeding with the virus ; but by this method rabbits are less 

 susceptible. Intravenous injection kills rabbits in three to six days. 

 The field and wood mouse, guinea-pig, ox, horse, ass, dog, cat, chicken, 

 goose, and duck are immune. Sheep too seem to be more disposed 

 to infection. 



The production of the disease in swine varies according to the breed ; 

 well-bred swine die from subcutaneous inoculation by rubbing on the 

 skin, and by feeding with the virus from cases of typical erysipelas. 



Post-Mortem Appearances in Swine. The skin is oedematous, 

 and infiltrated with blood ; the flesh is soft, greasy, and of a pale red 

 colour. The lymph-glands, particularly those of the mesentery, are 

 swollen and infiltrated with blood, presenting a red streaky appearance 

 due to engorgement and distension of the blood-vessels of the gland. 

 There is sero-fibrinous exudation of the pleura and pericardium. The 

 peritoneum is congested and covered with ecchymosed spots. The 

 mucous membrane of the bowel is highly congested and swollen, and 

 in many places the epithelium is desquamated, and occasionally partially 

 formed ulcers are present. The bacilli are widely distributed, but not 

 so plentiful in the blood as in the experimental animals. According 

 to Schottelius another bacillus is sometimes found associated with the 

 erysipelas bacillus in the organs. This organism, the Bacillus coprogenes 

 fcetidus, is found in the contents of the bowel and neighbouring organs 

 of animals affected with erysipelas. It is non-motile and shorter than 

 the Bacillus subtilis, and possesses spores. The cultures emit a putrid 

 stench. The presence of this organism in animals affected with ery- 

 sipelas is of no etiological importance. Some of the mild affections of 

 swine Urticaria or nettle rash and skin necrosis, and also endocarditis 

 verucosa bacillosa, are considered by Kitt, Bang, and Jensen to be 

 caused by the bacillus of swine erysipelas. The faeces of affected swine 

 are very virulent. The disease is spread by means of rats and mice. 



Immunity. The repeated passage of the erysipelas bacillus 

 through the pigeon renders it more virulent for swine, while its 

 passage through the rabbit, on the contrary, diminishes its virulence 

 for swine. After a time the virus obtained from the rabbit does not 

 kill the swine, but only makes them sick, rendering them immune to 

 the action of strong virus. The degree of attenuation obtained 

 persists in cultures made in ordinary bouillon, which is used as a 

 vaccine for swine. 



Pasteur's method consists in using two vaccines of different degrees 

 of virulence in doses of 0*12 c.c., an interval of ten days intervening 

 between the first and second inoculation. As young pigs are not so 



