MOSQUITOES 0:N- BOARD SHIP 349 



openings none were found. Iron water tanks, as a rule, are more securely 

 covered and are given more attention than the wooden containers. The tvvo or 

 three barrels, placed in front of the galley and forecastle, are more frequently 

 infested and in every instance perference was given them in the examination. 

 The box of the carpenter's grindstone offers another favorite place for the 

 breeding of this insect. An examination of the cabins was made to determine 

 the presence or absence of adult insects. In the room from which the man 

 with yellow fever was taken, the insects were found in abundance, both normal 

 and blood fed, resting in the shady corners on dark objects hanging around the 

 room. Considerable effort is necessary to detect mosquitoes when they are few in 

 number; each cabin should be gone over systematically, passing the hands in the 

 corners and gently shaking the hanging articles until every object above the 

 floor has been gently disturbed. The forecastle and galley of this schooner, 

 immediately behind the breeding barrels, harbored the insect in abundance. 



" The steamship William Cliff is of interest in connection with the trans- 

 ference of mosquitoes by vessels as well as furnishing data relative to the period 

 of incubation and spread of malaria among a crew where all outside influences 

 were removed. 



" Tliis vessel sailed from Liverpool, England, on May 29, 1902, with the fol- 

 lowing itinerary : 



Arrived. Port. Sailed. 



June 11 St. Thomas June 12 



June 15 Colon June 16 



June 19 Kingston June 20 



June 25 Tampico June 26 



June 27 Vera Cruz July 1 



" Until arrived in Tampico no sickness had occurred on board ; while leaving 

 that port one man was taken sick with a vague chill, and illy defined pains. Two 

 days later, June 28, four of the crew were taken sick with pronounced chills, 

 pains in the head, extremities, and back, and high fever. The following day, 

 June 29, four more including the captain, were taken sick in like manner; on 

 June 30, two more were taken sick. 



" On June 29, the blood of two of the cases was examined for the plasm odium 

 malaria with negative results. Their absence was accounted for by the large 

 doses of quinine administered prior to the examination. On July 1, two new 

 cases were examined; in one the tertian parasite was obtained, the other was 

 negative. 



" The disease clinically was of the tertian type, about half-intermittent, the 

 balance remittant. All, with one exception, responded readily to quinine. The 

 exception resisted the quinine for three days. An examination of the ship was 

 made to determine the genera and species of mosquitoes on board. Of these 

 there were three genera and four species in abundance, as follows : 



"Anopheles argyrotarsis, Culex fatigans, Culex tceniorhynchits, Janthinosoma 

 Lutzii. 



" All the varieties mentioned were found in the forecastle and after wheel- 

 house, the crew^s quarters being aft instead of forward. The cabins failed to 

 show the presence of mosquitoes on the examination of June 30, nor were any 

 noted previous to that time. 



"Anopheles argyrotarsis were present in Vera Cruz, though in very small 

 numbers; so scarce, that up to that time only one specimen had been taken. 

 This mosquito is also native to Tampico and Colon, According to the history 

 of the crew, which on such subjects is very unreliable, they stated that while at 

 Tampico they had not been molested by mosquitoes, while at Colon all hands 

 suffered severely from bites. The character of the fever is extremely suggestive 



