91 
from the city of Washington, and that I have had an opportunity to 
verify the condition of affairs as reported to me. 
The gentleman in question had seen in one of the newspapers some 
account of my Catskill Mountain experiments and wrote me through a 
mutual friend in Washington for detailed advice in his own case. Cor- 
respondence elicited the fact that the mosquito supply must come from 
a small mill pond one-eighth of a mile from his house, from a small, 
marshy tract above the pond, and from two horse troughs, one at his 
barn and the other at the roadside in front of his house. He had also 
a large rain-water barrel for which he immediately had a cover con- 
structed at my advice. 
The horse troughs were readily freed from u wrigglers" by using a 
small fine-meshed hand net every few days, and the kerosene treatment 
was used for the mill pond and the marsh. Estimating the surface area 
of the pond at 4,000 square feet, he sprinkled on 15 gallons of the cheap- 
est kerosene. This formed a continuous layer, and remained evident 
to the senses, in the absence of rain, for two weeks. Three weeks after 
the application, which was made on the 4th of June, I visited the place 
and found that the kerosene was still operative, although a slight shower 
had fallen on the seventeenth day. ~No trace of a living aquatic larva 
of any kind could be found, and the surface of the pond was thickly 
strewn with dead aerial insects, among them many female mosquitoes. 
A few straggling living mosquitoes were noticed about the house the 
first week in June, but none subsequently, and although the treatment 
was not repeated none have been reported to have appeared during 
July. 
The small marsh pools above the dam were treated at the same time, 
2 gallons of kerosene being used for this purpose. The ensuing drought, 
however, dried these pools up thoroughly and vitiated the experiment. 
The total expense of the treatment was $1.70 plus two hours light labor 
for two men, and the result was immunity from mosquitoes for the 
household and vicinity. 
This is a typical case of those which I had in mind when I expressed 
last year the opinion that there must be many localities where 3 by the 
use of these simple remedies, the mosquito plague may be averted. 
It may be well to add that I had the pleasure of receiving, in May 
last, a note from Dr. Robert H. Lamborn, the donor of the mosquito- 
essay prizes of two years ago, in which he says, " Your exact observa- 
tion regarding the treatment of insect-breeding waters with petroleum 
is most useful and it seems to me to be new." I trust it is understood 
that no novelty is claimed for the idea, but that I have simply recorded 
these experiences as showing conclusively that the remedy is not a theo- 
retical but a practical one. 
Mr. Smith had known of two recent cases of the use of coal oil for 
destroying mosquitoes on Long Island, and stated that the results sup- 
ported Mr. Howard's claims for the method. 
