316 The Philippine Journal of Science 1915 
they feed into the emerging imagines. The question of flies 
becoming infected by means of the pathogenic bacteria taken up 
by the larve from which they develop is of importance from a 
public hygienic standpoint. 
Concerning this question there have been but five investigators 
who have reported their results. The first of these, Cao, (31) 
in 1906, made observations upon the larve of the following 
diptera: Musca domestica, Calliphora vomitoria, Lucilia cesar, 
and Sarcophaga carnaria, they being feeders on putrefied meat 
or carrion. 
Feeding these larve on putrefied carrion, and then securing 
cultures from their intestinal flora, he demonstrated that death 
resulted in guinea pigs in from three to five days after being 
injected by these cultures. From the guinea pigs could be 
isolated a virulent strain of Bacillus coli, two or three varieties 
of typhoidlike organisms, and less frequently a pseudomalignant 
cedema bacillus, Staphylococcus aureus, an anthraxlike bacil- 
lus, and a very virulent Proteus fluorescens. 
The intestinal flora of the larvee were like those which are 
present during putrefaction, being Proteus vulgaris, P. mira- 
bilis, P. zenkeri, Bacillus subtilis, B. radiciformis, an anthrax- 
like bacillus, B. fluorescens liquefaciens, B. fluorescens non- 
liquefaciens, cocci, typhoidlike and colilike bacilli, and less 
frequently the sarcine, Bacillus prodigiosus, the oidia, and 
blastomycetes. 
As a result of his investigations Cao came to the following 
conclusions: 
The bacterial intestinal flora of larve is like the bacteria 
which occur in the putrefying meat upon which they feed. 
The intestinal flora consists of the Proteus group, the subtilis 
group, the fluorescent group, coli and typhoidlike organisms, 
and cocci. 
The bacterial flora is alike in the flesh of cold- or warm-blooded 
animals and alike in the different species of flies. 
The intestinal flora of larve acquired during feeding upon 
putrefied meat shows a greater virulence than those existing 
in the meat. 
The germs in putrefying dead animals are derived from the 
air, from their intestinal contents, from the blood of those 
dying of septicemia, and from flies as they deposit their eggs. 
The interior of the eggs of flies is sterile, but the shell contains 
many bacteria. 
