June, 1911 AMERICAN HOMES AND GARDENS i 
SOIL POLLUTION BY HOOKWORM 
INCE the discovery by Dr. Charles 
Wardell Stiles that the hookworm 
is responsible for the low mental 
and physical condition of the “poor 
whites” in many parts of the South, the 
problem of soil pollution has engaged the 
attention of the United States Public 
Health and Marine Hospital Service as 
well as of local health authorities. 
Under the direction of Prof. Stiles and 
Dr. Charles R. Gardner, experiments have 
been conducted with a view to determin- 
ing the length of time that hookworm 
eggs may retain their vitality in the soil 
under various conditions of drying and To get the best results with your camera, 
of temperature. From these experiments 2s ; Sg a ee 
it appears that it is not safe to assume that it is absolutely essential to equip it with a 
the sand under and around a privy is en- 
tirely free from infection with hookworm 
even five months after the privy was last 
used, although the infection is consider- 
ably reduced at the end of four months. 
Under water, where the fecal material 
undergoes decomposition, most of the 
hookworm eggs are dead in about ten 
weeks, though some survive that period. 
It seems very probable that in three 
months all hookworm eggs in fecal ma- 
terial would be dead if this material is 
subjected to decomposition; at any rate, 
it would not be safe to use such material 
for fertilizer in less than three months. 
Chloride of lime has been used as a 
disinfectant in solutions of about one 
pound to ten gallons of water. Experi- 
ments show that this solution does not 
kill all the hookworm eggs in from 22 to 
40 hours. B +S 7 
Incidentally these experiments brought ausch lomb Optical ©. 
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biggest noise the world ever heard,” half 
of the island of Krakatoa was blown away 
and every vestige of life was destroyed on 
the remaining half. The ground was buried 
under hot ashes and burning pumice 
stene, varying in depth from three feet 
to nearly two hundred feet. No vegeta- Sample and OP / A House Lined with 
ble germ could possibly have survived Circular 4 
the catastrophe. Yet, only three years 
@ 
after the eruption, when Krakatoa was y 
explored, various species of plants were & ; || ? [ ad () () 
found flourishing there. é 
It was shown that they could not have 
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been carried there by human agency, be- as shown in these sections, is Warm in Winter, 
cause men had not visited the devastated a Cool in Summer, and is thoroughly DEAFENED. 
island. The character of the new plants 3) The lining is vermin proof; neither rats, mice, 
was such as to prove that they could not x nor insects can make their way through or live init. 
have been derived from the former vege- 
tation of Krakatoa, even if any living re- 
mains of that vegetation could have ex- 
isted in the burned and buried soil. 4 WE 2 
The nearest land on which any plants CORRESPONDENCE SOLICITED 
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of ferns and several species of floweriny 
plants and grasses were discovered by Hy CROSS-SECTION THROUGH FLOOR. 
Treub flourishing on the shore and in the 
