Miscellaneous. 



440 



[November, 1910. 



half an inch deep in which to breed. 

 While their young or wrigglers must live 

 in water, they are also obliged to come 

 to the surface at intervals to breathe, 

 otherwise they would drown like other 

 air-breathing animals. 



After a long series of observations and 

 experiments covering several years, 

 tho Bureau of Science is in a position to 

 state with certainty that practically 95% 

 of the brown or night mosquitoes breed 

 in cesspool and stable vaults on premises, 

 while the other 5% breed in drains, 

 canals, tubes and ditches or stagnant 

 pools leading from cesspools and stable 

 vaults. 



If we will bear in mind that captures 

 of mosquitoes at night in dwelling 

 houses in various parts of Manila have 

 demostrated that 95% of such captures 

 consist of the brown mosquito, we will 

 see that the chief need is first to get 

 rid of these and this can only be 

 accomplished by first getting rid of 

 their breeding places. 



Cesspools and stable vaults in the city 

 ol Manila consist essentially of stone or 

 cement-lined pits of one to three com- 

 partments, sunk into the ground, hav- 

 ing an intake where refuse enters, one 

 two or three manholes for the purpose of 

 cleaning and a vent pipe of large 

 diameter and of varying length 

 for allowing foul gases to escape. Some 

 of these vaults have a drain pipe from 

 the last compartment connecting usually 

 with the street drains. 



In one of the vaults inspected in a 

 given typical area the covers to the man- 

 holes were defective, allowing adult 

 mosquitoes to enter and leave the vaults 

 with ease. On the other hand, vaults 

 which have tight manhole covers have 

 vent pipes out of which at early twilight 

 mosquitoes may be seen to come in 

 thousands. 



The Bureau of Science with the co- 

 operation of the Bureau of Health has 

 started a campaign of extermination 

 against mosquitoes found in cesspools 

 and drains. The preliminary measures 

 consist in pouring ordinary " petroleum " 

 into all the vaults and cesspools and 

 their outlets within a given distance 

 of the Philippine General Hospital, and 

 as fast as conditions permit, this work 

 is to be extended to all parts of the 

 city. It is obvious that oiling vaults 

 and cesspools by the government is only 

 a "temporary" and an "educational" 

 measure, intended to demonstrate to the 

 people that the mosquitoes can be gotten 

 rid for the time being. There will still 

 be a few adult mosquitoes which have 



already escaped from the vaults and 

 cesspools in a given area and until 

 these die [in say 14 to 20 days] people 

 will continue to have a few in their 

 houses, though these should diminish 

 steadily till all are gone. 



So much for what the government 

 purposes as an emergency measure. Now 

 the part that the people must perform 

 is plain. 



First. Let every householder see that 

 the manholes to his vault are tightly 

 covered so that there is no crack by 

 which adult mosquitoes can enter. 



Second. Let him see that there are 

 no broken sides left in vaults. 



Third. Let him pour \ cup of pet- 

 roleum into each compartment of his 

 house vault and his stable vault every 

 week or 10 days. 



Fourth. Let him have a piece of brass 

 wire gauze tightly fastened over the 

 vent pipe to his vault, and over the inner 

 end of the overflow pipe leading from 

 his vault or cesspool. 



Fifth. Let every person in Manila 

 remember that the brown mosquito is 

 the proven carrier of the dread filaria or 

 " night worm " and possibly of dengue 

 fever and that anyone is liable to in- 

 fection with either of these diseases if 

 bitten by the brown mosquito. 



The people of this city have little or 

 nothing to fear from the waters of 

 esteros, rice fields, grass fields, large 

 canals and ponds in so far as concerns 

 mosquitoes that annoy them at night. 

 While mosquitoes do breed in these last- 

 mentioned places in limited numbers, 

 they have many natural enemies such 

 as fish, beetles, waterbugs, etc., which 

 keep their numbers down and the habits 

 of the adult mosquitoes found in these 

 places are such that they almost never 

 enter dwelling houses. 



People should not think that because 

 of the simplicity of the measures above- 

 proposed they will not work. The thing 

 has already been proven here on limited 

 areas and there is no reason to believe 

 that it will not work for the whole city 

 if it will for a given portion. 



