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The presence of Anopheles in the pond at the Normal School was 
brought to the attention of the president, and the subject of drainage was 
broached. Objection was made that the water might be needed in case 
of fire, and I then suggested cleaning the edges of the pond as the next 
most efficient measure of control. 
The importance of draining the marsh near the negro school was im- 
pressed upon the president of the city Board of Health, and he took the 
matter up with the City Commissioners. 
2. Cleaning the Edges of Breeding-places——Where drainage is im- 
practicable, the next most effective means is cleaning the edges of pro- 
tective vegetation. While some species of mosquitoes do not seem to: 
care particularly for shade and protection, those of the genus Anopheles 
do, and thrive much better in it. Insects, small fish, and other animals 
which prey upon mosquitoes, have a much better opportunity to find and 
catch the wigglers when the protecting growth is removed. That they may 
often be exterminated by such means I am satisfied from the examina- 
tions of the Murphysboro sink-holes in the dry months of 1918 already 
referred to and illustrated in Fig. 15. As has been suggested, this method 
is especially useful with small streams, which of course can not be drained, 
and on which the use of the third remedy (oiling) is difficult. Open drains 
through town, which are not at all uncommon in southern Illinois, if 
they can not be replaced by covered drains, should at least be carefully 
cleaned. They should-be covered, if possible, as this both removes pro- 
tection and usually prevents the laying of eggs. If drains must be left 
open through town their beds should be so graded that the water will not 
form pools in dry weather. 
A special effort was made in Carbondale to advise the city author- , 
ities on this subject through the Board of Health, and during Health Pro- 
motion Week illustrated talks were made by the writer on the local sit- 
uation and all phases of control. It should be remembered that the edges 
of a pond or ditch should not be cleaned just once, and then left for the 
plants to grow up again, but that they should be kept clean continuously. 
Neglect of this precaution was illustrated in Thompson’s Lake when it 
was lowered eight feet to destroy a growth of- pond-lilies and cattails 
troublesome in boating. Much of the growth was killed, but so many 
plants grew up again that Anopheles bred almost as abundantly as before. 
3. Oiling—Oiling may be used to smother the mosquito larvae in 
the water, in conjunction with cleaning operations. The surface film thus 
formed prevents the larvae and pupae from reaching the air necessary to 
their respiration. A rate of application commonly recommended is an 
ounce of oil to fifteen square feet of water surface. Prof. W, B. Herms, 
of California, finds that application of oil by the dipperful is very waste- 
ful and uses a knapsack sprayer instead. Flowing streams may be oiled 
by means of drip cans so arranged that oil will drip from them at a rate 
of about twenty drops a minute. A mixture of kerosene with a heavy 
fuel oil, half and half, is better than pure kerosene, because it spreads 
