BACILLUS OF MOUSE SEPTICAEMIA 195 



susceptible to the disease as older ones, they are more suitable for 

 immunization. Swine vaccinated by this method remain immune for 

 one year, which is long enough for breeding and fattening purposes. 



Lorenz has introduced a method of protective inoculation with 

 the blood serum of swine previously immunized. The serum is 

 obtained in the following manner : Healthy swine are first inocu- 

 lated with serum, and then with a virulent culture shortly before 

 the blood is withdrawn. Blood serum of an animal inoculated in 

 this manner confers immunity on other animals. A pig weighing 

 eleven stones, supplies on an average 750 c.c. of serum ; out of this 

 quantity about 150 grammes of a stable substance is prepared, con- 

 taining only i volume of serum, 30 per cent, glycerine and 40 

 per cent, water. It is very difficult to procure a serum of uniform 

 strength in swine erysipelas, because it is not easy, and often impos- 

 sible, to obtain a uniform grade of virulence in swine erysipelas 

 cultures. The serum is injected subcutaneously behind the ear or 

 between the thighs. 



BACILLUS OF MOUSE SEPTICAEMIA. 



(Bacillus Murisepticus.) 



This is an experimental infectious disease found by Koch. The 

 grey and white mouse, when inoculated subcutaneously with putrid 

 blood or meat infusion, died of septicaemia due to the Bacillus 

 murisepticus. 



Microscopical Appearances. Morphologically identical with the 

 bacillus of swine erysipelas ; the bacilli occur mostly in the cells. (See 

 Photomicrograph, Plate III., Fig. 15.) 



Motility. Undecided (Giinther). 



Staining Reactions. Are similar to the bacillus of swine erysipelas. 



Spore Formation. Was observed by Koch in one case (Giinther). 



Biological Characters. The appearance in gelatine stab cul- 

 tures is very characteristic, the growth resembling a test-tube brush. 

 (See Photograph, Fig. 76). The growth in the other media is identical 

 with that of the bacillus of swine erysipelas. 



Pathogenesis. Affects grey and white mice, which die in the same 

 characteristic sitting position described with mice inoculated with the 

 bacillus of swine erysipelas. Field-mice, chickens, and guinea-pigs are 

 immune. Schiitz considers that the bacillus of mouse septicaemia and 

 swine erysipelas are probably identical. 



