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 \vere 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 w r ere 

 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- 



