MICROCOCCUS LANCEOLATUS. 505 



culture of the micrococcus, usually results in the death 

 of these animals in from twenty-four to forty-eight 

 hours. The course of the disease produced and the 

 post-mortem appearances indicate that it is a form of 

 septicaemia what is known as sputum septicaemia. 

 After injection there is loss of appetite and great 

 debility, and the animal usually dies some time during 

 the second day after inoculation. The post-mortem 

 examination shows a local reaction, which may be of 

 a serous, fibrinous, hemorrhagic, necrotic, or purulent 

 character; or there may be combinations of all of these 

 conditions. The most marked pathological lesion is 

 the enlargement of the spleen, which in mice is con- 

 spicuous and common, and in rabbits not so much so. 

 It is sometimes hard, dark colored, and dry, or it may 

 be soft and bright red. The liver also is sometimes 

 dark colored and gorged with blood, but more fre- 

 quently it is paler than normal and rich in fat. The blood 

 of inoculated animals immediately after death often 

 contains the micrococci in very large numbers. For 

 microscopical examination they may be obtained from 

 the blood of the veins, arteries, or cavities of the heart, 

 and usually from the pleural and peritoneal exudations 

 when they are present. 



Mice and rabbits are the most susceptible animals, 

 and are thus usually employed for experimental pur- 

 poses in investigations with this micrococcus; but 

 guinea-pigs, dogs, cats, rats, and sheep are also sus- 

 ceptible. Chickens and pigeons are insusceptible- 

 Young animals, as a rule, are more easily affected 

 than old ones. In dogs subcutaneous injections usually 

 give negative results. True localized pneumonia does 

 not usually result from subcutaneous injections into 



