INITIATING THE CAMPAIGN 69 



Where practicable, data for the 2 years previous should be 

 obtained; if this is not possible figures for the preceding year 

 will do. At the conclusion for the season's work, a second census 

 should be taken, using the same card for the same house and 

 recording the second results below the first. This will show the 

 comparison in incidence for each family, before and after initiating 

 the work. 



THE SURVEY 



As soon as it has been determined by means of the collection 

 of statistics relative to the incidence of the mosquito-borne 

 diseases in the community, that an anti-mosquito campaign 

 would be justified, the next step is to make a survey of the pro- 

 posed area of operations, with a view to ascertaining the probable 

 cost of such a campaign. If at all possible, this should be done 

 by a sanitary engineer familiar with costs of this kind of work. 

 Frequently State Departments of Health will send an engineer 

 to make such a survey gratis. 



The following suggested mode of procedure in making the 

 survey and estimate is taken from the instructions issued 

 sanitary engineers engaged in the co-operative anti-malaria 

 demonstration work of the U. S. Public Health Service and the 

 International Health Board: 



"Assuming that it is concluded, from information gathered, that the 

 making of a survey is worth while, obtain, if available, a map of the area 

 involved or make a copy of an existing one. If none has been pre- 

 viously made, you will make a sketch map as you proceed. (Maps 

 generally may be obtained from the city authorities; if not, an insurance 

 map may be borrowed from a fire insurance agent.) 



"On this map, mark all water-courses, swamps, ponds, ditches, wet 

 lands, land subject to overflow and other wet places or possible sources 

 of mosquito-breeding. On flat lands, make inquiry as to how long water 

 stands thereon in wet periods; look for vegetation that is indicative of a 

 high water table. Let the map extend to about half a mile from the 

 residences on the outskirts of town. 



WHAT TO OBSERVE 



"It is next necessary to note the ditching and filling and clearing or 

 regrading (of streams and old ditches) that is essential and that which 

 will probably be necessary. It is not advisable to make estimates for 

 ditching from observations immediately after rain-storms. The infor- 

 mation must be carefully gathered; the character of soil, amount of 



