ZOOLOGY AND BOTANY, -MICROSCOPY, ETC. 
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Nematodes in the soil, by their characteristic structure and movement. 
A slightly higher percentage of larvae can be isolated from moist than 
from saturated soil. In soil with very finely divided particles the 
percentage of larvae that can be isolated is less than in coarser soils. 
The apparatus can be used for other Nematodes in the soil. J. A. T. 
Chickens and Hookworm. — James E. Ackert ( Amer . Journ. 
Hygiene , 1922, 2, 26-38). An inquiry into the role of chickens in 
disseminating hookworms. The length of time required for food 
material to pass through the digestive tract of chickens ranges from 
two hours and forty minutes to sixteen or more hours. Hookworm 
eggs remain viable while passing through the alimentary canal of 
chickens and are able to hatch ; they may produce infective hookworm 
larvae when the fowl faeces are mixed with animal charcoal or soil. But 
the majority of the eggs come to nothing. Newly hatched larvae 
swallowed by chickens can pass through the alimentary tract apparently 
uninjured. Sheathed hookworm larvae swallowed by chickens fail to 
pass at once through the fowls uninjured. A comparison of the reduc- 
tion of mature hookworm larvae by fowls with the establishment of 
infective spots by them convinces the investigator that chickens are 
more beneficial than harmful in the control of hookworm disease in 
Trinidad. J. A. T. 
Pigs and Hookworm.— James E. Ackert and Florence K. 
Payne ( Amer . Journ. Hygiene , 1922, 2, 39-50). An inquiry into the 
role of swine in hookworm dissemination. Human hookworm eggs 
swallowed by domestic pigs produce infective larvae in five days during 
the rainy season in Trinidad. A high percentage of the eggs ingested 
produce infective larvae. The free-range pig is an important factor in 
the dissemination of human hookworm eggs. Infective hookworm larvae 
swallowed by pigs do not pass through unaltered in the excrement. 
Larvae of Strongyloides stercoralis survive passage through the digestive 
tract of the pig and multiply in the faeces. The pigs become infected 
with this Nematode. A new species of hookworm, Necator suillus , is 
of common occurrence in the domestic pigs in Trinidad. J. A. T. 
Unsheathed Hookworm Larvae in the Soil. — W. W. Cort, D. L. 
Augustine, J. E. Ackert, F. K. Payne, and G. C. Payne (Amer. 
Journ. Hygiene , 1922, 2, 17-25). Although various investigators have 
reported that mature hookworm larvae lose their sheaths under certain 
conditions, it has been the general opinion that they live normally 
enclosed in sheaths. It was found by the investigators that in a series 
of soil samples examined from places polluted by people infested with 
hookworms a large proportion of the mature larvae were without sheath. 
Also, in experiments on the conditions under which hookworm eggs 
hatch and develop, and on the migrations of the infective larvae, it was 
found that in soil a large proportion of the larvae soon became 
unsheathed. These findings suggest that it is a common thing for 
mature hookworm larvae to lose their sheaths and continue to live in 
soil. Since most of the knowledge of the activities of mature hookworm 
larvae has come from studies on sheathed forms, it will probably be 
necessary to revise some of the conclusions. J. A. T. 
