356 ENTOMOLOGICAL NEWS. [Oct., ’08 
was not sufficint to kill the parasites in this peculiar environ- 
ment. It appeared that a blanket of pure air enveloped the 
rodent’s body which the gas would not penetrate in the three 
hours of sulfuring. After these facts were established an 
exposure to five hours was the minimum time set. In an expos- 
ure to five hours this hypothetical layer of air surrounding the 
animal’s body was presumably destroyed and the fleas exposed 
directly to the sulfur fumes. Endeavoring: to escape, the fleas 
would jump about when the rats became blind and succumbed 
to the slowly penetrating sulfur fumes. Some were found on 
the floors of the holds and the comparatively few fleas found 
on the rat were asphyxiated in attempting to extricate them- 
selves or jumped on the rat from the floor when the deadly 
fumes were becoming effective. Evidence of this was obtained 
in the fact that all the specimens collected from the rats were 
found clinging to the ends of the hairs. 
When a vessel had received its fourth or fifth fumigation, 
providing the captain had observed the legal precautions (keep- 
ing the vessel fended off six feet and wearing rat guards on 
all her lines when alongside the docks) the rats aboard proved 
to be a negligible quantity. Efforts were taken under these 
circumstances to collect the fleas directly from the holds by 
means of fly-paper wound about the shoe tops of a person who 
walked through holds and between decks. This method proved 
ineffectual for trapping purposes, though it is followed with 
success when fleas are plentiful. The claim made—perhaps 
on unsubstantiated evidence—that live fleas invariably leave 
the dead body of a rat is considered untenable. I have found 
fifteen live fleas on the carcasses of forty black and brown rats. 
These had been cold for thirty-six hours, showing signs of de- 
composition. Dr. Hobdy, Chief Quarantine Officer of the 
United States Public Health and Marine Hospital Service, lo- 
cated a number of dead rats in a stable near the harbor. Four 
of these were examined by him and showed about sixty live 
fleas in the cervical region of each. These rats had been dead 
for at last forty-eight hours, infested as they were with half- 
grown larvae of blow flies. At the City Board of Health head- 
