BACILLI WHICH CAUSE GASTRO-ENTEKITIS. 331 



The effect obtained is, however, not uniform, but 

 varies according to the virulence of the individual 

 species, as well as according to the number of bacteria 

 introduced and the seat of their application. After Symptoms in 

 the injection of large quantities into the veins the the animals - 

 animals become collapsed in a very short time and 

 die in from one to three hours. Where smaller 

 quantities are employed vomiting sometimes occurs, 

 followed by profuse diarrhoea, the stools being often 

 mixed with blood, and ultimately collapse, and death 

 occurs after 12 to 24 hours. Some species of bacteria 

 cause a passing diarrhoea, without any further bad 

 result, after intravenous injection of very small doses 

 or after the subcutaneous introduction of medium 

 doses. We cannot as yet properly explain this action 

 of the bacteria. We do not usually find, either in the 

 acute or in the protracted cases, any sufficient multipli- 

 cation of the bacteria injected to explain the phenomena, 

 and it has also been observed on some occasions that 

 the same results follow the injection of sterilised 

 cultivations. These two facts seem to indicate that we 

 do not have here to do with the immediate action of the 

 bacteria, but with the toxic effect of a substance which 

 has been produced by the bacteria. More elaborate 

 investigations will probably give us information as to 

 this point. 



The organisms which act in this way cannot be 

 looked on in all cases as specific pathogenic organisms ; 

 some of them are mainly saprophytes, or exciting 

 agents of putrefaction, while many belong to the 

 forms of bacteria previously described, which, when 

 inoculated in small quantities, set up diseases, mostly 

 forms of septica3mia, which run a slower course, but, on 

 the other hand, when introduced into the blood stream in 

 large doses, lead to the sudden illness just described. 

 Thus, for example, we obtain these results with the Enumeration 

 bacilli of rabbit septicaemia, in a very marked manner bacteria be- 

 with the bacillus crassus sputigcnus, the bacillus of lon ^ n ^ to this 

 pneumonia, and, among the bacteria which are chiefly 

 saprophytic, with the bacillus ruler indicus. It must 



