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trees. My irrigating ditch, a dozen feet wide, of sluggish current, runs through the 
grove beside the house. There has never a single mosquito larva been seen in the 
ditch from where it enters the first shade of these trees to where it emerges from them 
200 yards away, while above and below mosquito larvee are plentiful—not imme- 
diately below, but some hundreds of yards away, where the water stands in pools 
and becomes stagnant among a growth of black walnuts and cottonwoods. 
My live stock pasture in this timber, going into the walnuts and back again under 
the eucalyptus shade at pleasure. Frequently when the cows come up at night they 
bring a swarm of mosquitoes; occasionally some of them get into the house, but 
cause us so little annoyance that we scarcely notice them. Before this ditch reaches 
the Eucalypti it runs through a jungle of ‘‘fence bamboo’’ (Arundo macrophylla), 
where the mosquitoes are so bad that we avoid working there except on the windiest 
days. And, though the ditch has more current there, the larvae of mosquitoes are 
plentiful in the water till it reaches the Eucalyptus trees, below which point none 
are found till it has become stagnant away below them. 
People who have camped aiong the willows of Kings River, only a few miles 
away, have come here with faces so blotched and swollen from mosquito bites as to 
be hardly recognizable, and have camped in the shade of ‘‘Sanders’s gum trees,’’ as 
my grove is popularly called, for weeks, and declare that they never even heard a 
mosquito sing during that time. 
To the non-botanical reader I may say that this species of Eucalyptus is very tender 
to frost. The coldest weather ever known here, 19° F. above zero, killed thousands 
of them. 
Dr. Nuttall points out that the planting of eucalyptus trees is not a 
sovereign remedy, from the fact that malaria still prevails at Tre 
Fontane, outside of Rome, in spite of Eucalyptus plantings. The 
mere planting of trees, however, is undoubtedly of use in malarial 
districts, since it will modify the condition of drainage of the soil. 
In view of Mr. Sanders’s strong evidence it really appears that plant- 
ing of eucalyptus trees will be worth while in certain locations, not 
entirely (on account of the conflicting and not thoroughly satisfactory 
evidence) for mosquito protection, but incidentally for this use as well 
as other purposes. 
DRAINAGE AND COMMUNITY WORK. 
After all, the best of the means which may be adopted against mos- 
-quitoes will always consist in the abolition of their breeding places. 
Small pools with stagnant water can be treated, but it is a great deal 
better to drain them or to fill them up. Swamp areas must sooner or 
later be drained. It is perfectly obvious that the sooner this is done 
the better from every point of view, not only from that of human 
health but from the increased value of real estate in the neighborhood 
and from the practical value of the reclaimed land itself. The time is 
coming, and rapidly, when this drainage of large swamps will not 
remain a matter which concerns the individual owner of the land, but 
one for town or county action, and even for States. The report of 
T. J. Gardner on the policy of the State respecting drainage of large 
swamps, published in the Report of the Board of Health for New York, 
