REPORT ON MOSQUITOES. 57 



Tooms from the outside so as to give the gas a chance to escape 

 •or become dihited before they are entered. Incidentahy this 

 treatment will reach rats, mice and other vermin as well. For 

 large spaces this is much the cheapest process and, used with a 

 .knowledge of the danger involved, is reasonably safe. 



Sulphur bunied over a water bath at the rate of one pound 

 for every 500 cubic feet of space is another effective agent; but 

 this attacks metal and bleaches fabrics, so its use is excluded in 

 many places. Where, however, there is nothing to be harmed by 

 it, the large sulphur candles made for disinfecting purposes may 

 be satisfactorily employed by burning on a brick in a tub or 

 other shallow vessel partly filled with water. This is also a 

 reasonably cheap application. 



Formaldehyde stupefies but does not kill and the same is true 

 'Of pyrethrum, tobacco and some other narcotics, all of which also 

 are too expensive when used in such cpantities as might be 

 expected to make the stupor permanent. 



With this introductory explanation the importance of Mr. Kel- 

 ler's results will be apparent, because the Datura stramonium or 

 "T'ltipson w^eed," which he found effective, occurs almost every- 

 where and may be prepared by anybody at small expense, and 

 because it is harmless to man in such quantities as might escape 

 from a well closed cellar into a dwelling house above. 



Mr. Kclle/s Report. 



Pursuant to your request, I beg leave to submit a report on the investigation 

 and experiments carried on by me to find a practical method of destroying the 

 hibernating species of mosquitoes. Contrary to the statements made, that 

 none of these troublesome creatures were to be found in hibernation in the 

 particular territory where I carried on my investigations, my results prove 

 that hibernating mosquitoes are found more or less numerous in at least 75 

 per cent, of all the cellars in the city of Newark. Of 24 cellars, situated in 

 different sections of the city, I found mosquitoes present in 17. For conveni- 

 •ence I shall number these infested cellars consecutively, numbers i to 17. 



Cellars numbered i, 2 and 3 were located on Seymour avenue; moisture 

 •quite noticeable, although floors were cemented, brick foundation, not white- 

 washed. Mosquitoes were found in numbers congregated near the water- 

 supply pipe, especially in cellars 2 and 3. In cellar number i, however, the 

 insects were not found in colonies, but all over, having been disturbed several 

 ihours before I inspected the place. 



Cellars numbered 4 and 5 are located on Springfield avenue. Cellar number 

 4 was fairly moist, walls whitewashed, but not of recent date, brick founda- 

 tion. In this cellar a considerable number of mosquitoes were found, but all 

 in somewhat of a dazed condition. They would not fly or crawl from their 

 "hiding places even if urged on to do so, and hundreds were found clinging to 

 the wall in the dark portions of the cellar. Cellar number 5 was quite dry, 

 not whitewashed, and here large stones were used in building the foundation. 

 Ventilation not very good. Mosquitoes were found in very small numbers. 



Cellars numbered 6, 7 and 8 are located on Hunterdon street. Cellar num- 

 ^ber 6 was quite dry, cemented floor, brick foundation, partly but not recently 



