XI] BACILLI ; SPECIFICALLY PATHOGENIC 227 



The general morphological and cultural characters are 

 those of bacillus coH. As stated just now, from the lung 

 juice pure cultures were obtained, the organism being 

 present in the lungs in great abundance (see Fig. 78). The 

 bacilli are o"3-o'4/i thick, o'8-i'6yu, long. 



The cultures as also the lung juice act virulently on mice 

 and guinea-pigs, on the former more than on the latter. 

 Subcutaneous inoculation produces disease and death in the 

 course of thirty to one hundred hours. On post-mortem 

 examination both lungs are found intensely inflamed, 

 some portions in a state of red hepatisation ; generally there 

 are present pleurisy and pericarditis and peritonitis, with more 

 or less sanguineous exudation. The spleen is enlarged in 

 mice, but not in guinea-pigs. The bacilli can be easily 

 demonstrated in very large numbers both by cover-glass 

 specimens and cultures in the heart's blood, the lung juice, 

 and the spleen of mice, and in the lung juice of guinea- 

 pigs. 



The lung juice, or cultures derived from the tissues of 

 the infected mice or guinea-pigs, inoculated into further mice 

 or guinea-pigs, produce the same disease and death with the 

 symptoms just described. 



While working with cultures of these bacilli on mice 

 and guinea-pigs there occurred amongst normal mice and 

 guinea-pigs kept in the same stalls as the experimental 

 animals an epidemic of pneumonia, leading to the death 

 of a great many of them ; on post-mortem examination all 

 showed exactly the same appearances as those experimental 

 mice and guinea-pigs, and the juice of the inflamed lungs 

 contained the bacilli in crowds. 



Three monkeys, kept on the same premises, and which 

 most probably became accidentally infected by food, died of 

 pneumonia. In the inflamed lungs the bacilli could be 



