296 Illinois State Laboratory of Natural History. 



observed. As a consequence of this purging, the body would 

 become soft and flaccid and somewhat shrunken, an appear- 

 ance not presented by those in which the purging did not 

 occur. Occasionally some portion of the body, usually the 

 central or posterior part, became darker before death, but much 

 more commonly the larva retained its natural hue. The 

 approach of death was gradual, the affected insect becoming 

 more and more sluggish and insensible to irritation. Post 

 mortem changes were neither so rapid nor so extreme as in the 

 cabbage worm, owing probably, in part, to the thicker and 

 tougher skin. 



The fluids escaping from the vent were microscopically 

 examined, and found always swarming with bacteria, many 

 of them not infrequently having the flagellate motion of 

 Bacterium proper, but the greater number of them being 

 clearly Micrococcus. If a droplet of the blood were obtained 

 before death, it rarely gave any evidence of bacterial affection, 

 the only cases in which this was seen being those in which an 

 ante-mortem blackening of the body was observed. After death, 

 however, the blood invariably swarmed with the same bacterial 

 forms which were found earlier in the intestine, the ordinary 

 septic species soon developing rapidly. The alimentary canal 

 usually contained, both before and after death, vast numbers of 

 Micrococcus, and also, not infrequently, true Bacterium, but 

 bacilli or other bacterial forms were rarely found. The micro- 

 cocci occurring were not by any means as uniform as in the 

 cabbage worm and silkworm, both spherical and oval species of 

 various sizes often appearing on the same slides. The intestine 

 was commonly filled with food little, if at all, digested. In only 

 one instance was the alimentary canal empty and partly filled 

 with gas. 



THE CHARACTERISTIC BACTERIA. 



The bacteria which, from their abundance and uniform 

 presence, must be regarded as characteristic of 'this affection, 

 occurring as they did in the still living larvse almost to the 

 exclusion of other forms, were oval and spherical micrococci, 

 sometimes one, sometimes the other, and sometimes both corn- 

 mingled in variable proportions. The oval micrococci were 



