386 SANITARY ENTOMOLOGY 



find that it acquired pathogenicity by passage through the intestines of 

 the insect with or without otlier foods. 



Bacillus ''proteisimile'" Cao. An organism virtually described under 

 this name was isolated b}' Cao from the feces of Blatta orientalis in two or 

 more series of experiments in three different strains of varying virulence. 

 One strain retained its virulence in successive passages for five months. In 

 two experiments in which starved cockroaches with nonpathogenic feces 

 were fed on nonvirulent cultures of this germ and on a diet of bread 

 with putrid infusion of beef liver, and on a diet of 1 per cent infusion 

 of peptone, this germ became intensely pathogenic in the first case, killing, 

 when inoculated, a guinea pig in two or three days, and in the second case 

 in 36 to 40 hours, with acute septicemia. 



Bacillus "pseu^oedema maligno'^ Cao, cause of MALIGNANT 

 PSEUDOEDEMA, was isolated by Cao in one instance from a series of 

 B. orientalis, and he found it retaining its virulence in successive passages 

 through many months. 



Bacillus radiciformis Tataroff, a saprophytic organism found in water, 

 was isolated by Cao from the feces of Blatta orientalis in a single series 

 of experiments. In all of his tests with this organism, he did not find 

 that it acquired pathogenicity by passage through the intestines of the 

 insect with or without other foods. 



Bacillus " simile arh on chio^'' Cao, an organism described by Cao as simi- 

 lar to B. anthracis, was isolated in pathogenic strains from Blatta 

 orientalis by Cao. In one series of experiments it was isolated from a 

 number of B. orientalis, the feces of which, when inoculated into a guinea 

 pig, caused its death in 42 hours. From pure cultures isolated from the 

 feces, it was inoculated into a guinea pig and caused its death in 40 hours, 

 with intense sero-sanguinolent edema and an enormous spleen. The organ- 

 ism was recovered from the heart blood. A cony inoculated with pure 

 culture died in 48 hours, with symptoms similar to those found in hematic 

 carbuncle. The germs were still found in the feces of the cockroaches 

 after 21 days fasting and retained their virulence, causing death with 

 formation of a tumor on the spleen, but less intense. It maintained its 

 virulence in successive passages through many months. When fed to 

 starved cockroaches with nonpathogenic feces, two nonpathogenic strains 

 (one from soil and one from the feces of Calliplwra vomitoria) failed to 

 increase their patliogcnicity when eaten alone, or when combined with 

 sterile bread, sour milk, putrid milk, rotten egg, and fresh flesh; but one 

 strain obtained slight pathogenicity when eaten with putrid flesh, moderate 

 pathogenicity when combined with human feces, and intense pathogenicity 

 Avhen eaten Avith a diet of bread and putrid beef liver, a diet of bread 

 and 1 per cent infusion of peptone, or a diet of bread and an infusion of 

 putrid beef flesh. 



