DISPERSAL THROUGH TRANSPORTATION 299 



In Public Health Reports, vol. 21, no. 23, published July 8, 1906, there is 

 an interesting report from Surgeon Wightman, of the Public Health and 

 Marine-Hospital Service, dated May 5th, in which he states that the steamer 

 iMXor left San Francisco February 9th and proceeded to Guayaquil via Mexican 

 and Central American ports, leaving Corinto, the last Central American port, 

 on March 7th. She also called at four South American ports north of Guayaquil. 

 No mosquitoes were seen on board in any of these ports except at Corinto, and 

 these did not stay "wdth the vessel after leaving port. The Luxor reached the 

 quarantine station at Guayaquil at 9 a. m. on March 18th, passed inspection, 

 and passed up the river, anchoring a few hundred yards from the city. She 

 carried a cargo of lumber forward and aft ; that aft was discharged, but forward, 

 near the forecastle, it remained on deck, was wetted with rain and formed a 

 hiding-place for mosquitoes. Large numbers of mosquitoes came on board. 

 Anopheles was recognized, but not Aedes calopus. The vessel remained four 

 days and five nights, leaving March 23d. She arrived at Pieta, Peru, at 11 a. m., 

 March 24th, and the holds were fumigated lightly. No mosquitoes came on 

 board. She sailed that night for Callao, and a few active mosquitoes were seen 

 on board. The steamer arrived at Callao at 4 a. m., March 27th. All the crew 

 passed inspection, but were told to expect detention until the 29th. The work of 

 discharging the cargo, including the lumber on the forward deck, was begun. 

 March 27th, at 6 p. m., that is four days and fifteen minutes after leaving Guaya- 

 quil, a fireman was reported sick. The case was not reported to the authorities 

 until the 29th, when yellow fever was diagnosed and the patient removed to 

 a quarantine ship. The same night the second forecastle and second and third- 

 class quarters were fumigated and kept closed for 24 hours. The next morning 

 a second case developed, and April 1st the remaining portions of the vessel were 

 fumigated. April 4th a third case was reported, and a fourth case developed 

 April 7th. The whole vessel was fumigated throughout. April 8th the fifth 

 case developed. The first, third and fifth cases died, the last death occurring 

 April 11th. The vessel was ordered south to a colder climate by the Peruvian 

 authorities, and the subsequent history was good. None of the people aft were 

 infected. 



Doctor Wightman concluded that the insects probably gained access to the 

 vessel in the covered lighters rather than by flying; that the fire room, usually 

 regarded by seafaring men as never infested with mosquitoes, is under grave 

 suspicion; that the futility of partial fumigation is plain — even the life-boats 

 should receive attention ; that there is danger of harboring these insects in deck 

 cargo, and that possibly calopus may be present on a ship without detection, 

 even when carefully searched for. 



We have indicated, in the section on the carriages of mosquitoes by railroads, 

 ships and other conveyances, that the yellow-fever mosquito is frequently carried 

 in the summer time by railway trains and ships far beyond its permanent habitat, 

 and that even in these abnormal locations such mosquitoes escaping from trains 

 or ships may, in the warm weather, find suitable breeding-places and produce 

 one or more generations of adults. This process is going on every summer in 



