2o6 MICRO-ORGANISMS AND DISEASE [chap. 



colony does not exceed one to two millimetres. In stab 

 culture the stab is occupied by a whitish line ; under a 

 glass this is seen to be made up of minute droplets and dots, 

 whitish in reflected, yellow-brown in transmitted light. In 

 streak cultures the streak is represented by a narrow whitish 

 band of irregular outline and thicker in the middle than at 

 the margin. Gelatine is not liquefied by the growth. 



Rabbits, mice, fowls, pigeons, and sparrows are very 

 susceptible (Koch) to the inoculation of very minute doses 

 of culture or of blood of an animal previously dead of the 

 disease ; guinea-pigs and rats are unsusceptible (Koch). 

 When inoculated with a trace of the blood of a rabbit dead 

 of the disease, or with a trace of culture, rabbits show already 

 after ten to twenty-one hours a distinct rise of temperature ; 

 in severe cases the animals show spasms, rapid fall of tempera- 

 ture, already before the end of the first sixteen hours, and are 

 dead before the day is over ; but in some cases, particularly 

 after inoculation with minute traces of culture, death does 

 not take place before thirty-six to forty-eight hours. The 

 bacilli are found very numerously in the blood-vessels of all 

 organs. Spleen and liver, lymph glands and lungs, are 

 highly congested, so also the intestines ; extravasations are 

 only rarely found, and then only in the omentum and lungs ; 

 peritonitis is only noticed in a small percentage of cases, 

 and then only when the omentum shows the extravasations; 

 the serous coverings of the intestines are greatly injected. 

 As a rule, these symptoms are greatly more pronounced if 

 death does not occur before the second day. 



A bacillus closely related to this is the one which causes 

 acute septicaemia in guinea-pigs and mice, and which I 

 obtained from the pleural exudation of mice and guinea-pigs 

 that had died spontaneously from septicEemia — that is to say, 

 in which no primary cause could be assigned, and in which 



