DESCRIPTIONS OF PATHOGENIC BACTERIA. 151 



poisoning ; at times, however, it is very virulent 

 and multiplies in the organism so that a true 

 infection exists. It has been found in cases 

 of general hsemorrhagic sepsis and severe 

 diarrhoea in children ; in such cases however 

 the toxic action appears to be more conspicu- 

 ous than the effects due to multiplication of 

 the organism. Occasionally, it is found also 

 in the inflammation of serous membranes, 

 while upon wounds it attracts attention more 

 by the discoloration of the bandages which it 

 produces than by its growth. 



In the case of these two putrefactive bacteria 

 the distinction between intoxication, real toxic 

 action, and real infection is not sharply marked. 

 Only in regard to their occurrence in human 

 beings need this distinction be taken into con- 

 sideration ; there they produce their effect 

 chiefly through intoxication. In this connec- 

 tion it may be mentioned in passing that bac- 

 teria which are wholly without effect upon man 

 and the higher animals, and which are for them 

 neither infectious nor toxic, may yet be infec- 

 tious for lower organisms, such as insects. An 

 instance of this is the infection of flies by the 

 hay bacillus. 



Bacteria, which are neither toxic nor 

 infectious may yet prove fatal to warm- 

 blooded animals when injected in very great 



