ABOLITION OF BREEDING PLACES. 21 



same spot was passed again and a cloud of mosquitoes was seen issu- 

 ing from the crack so abundantly that at a little distance it seemed 

 like a stream of smoke. A little kerosene put a stop to this. 



Fountains and ornamental ponds are frequent breeding places, 

 and here the introduction of fish, as indicated in another place, is 

 usually all-sufficient. It frequently happens, however, that the grass 

 is allowed to grow down into the edges of ornamental ponds and 

 mosquito larvae find refuge among the vegetation and so escape the 

 fish. Broad-leaved water plants are also often grown in such ponds, 

 and where these broad leaves lie flat upon the surface of the water, 

 as they frequently do, one portion of a given leaf may be submerged 

 so that mosquito larvae may breed freely in the water over the sub- 

 merged portion of the leaf, protected from fish by the leaf itself, the 

 fish rising from below. It is necessary, therefore, to keep the edges 

 of such ornamental ponds free from vegetation and to choose aquatic 

 plants whose growth will not permit of mosquito-larvae protection. 

 In many small country towns, even where there is a water supply, 

 tanks are to be found under the roofs to supply bathrooms. Such 

 tanks should be screened, since mosquitoes gain entrance to the tank- 

 room either through dormer windows or by flying up through the 

 house from below in search of ovipositing places. About a large 

 old house there are so many of these chance-breeding places that only 

 the most careful and long-continued search will find them all. Fre- 

 quent change of water or the use of kerosene will render them all 

 harmless. 



In community work in cities all of the points mentioned must be 

 borne in mind, and in the portions of the community where the resi- 

 dences are for the most part detached villas, in the absence of 

 swampy suburbs the householders are in the main responsible for 

 their own mosquitoes. There are, however, breeding places for which 

 the municipality may be said to be responsible and these entirely 

 aside from public fountains, reservoirs, or marshes. It seems un- 

 likely that in any general sewerage system mosquitoes may breed 

 in the sewers proper. That they do breed in the catch-basins is 

 well known. The purpose of the catch-basin is to catch and retain 

 by sedimentation sand and refuse which would otherwise enter the 

 sewer and deposit in it. It is intended to be watertight and to hold 

 a considerable body of water which stands in it up to the level of the 

 outlet pipe. Such catch-basins are very commonly used in back 

 yards and at the crossings of streets. The water is removed only 

 by rain or when street or yard surfaces are washed. In dry seasons 

 the period of stagnation may last several weeks, certainly Long enough 

 for mosquito breeding. As a matter ot fact, mosquitoes in midsum- 

 mer do breed in such basin traps or catch-basins by millions. In 

 the work against mosquitoes in Brookline, Mass., in 1901 and 1902, 



