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Parasitic Arthropoda 
infested it may be necessary to thoroughly scrub the floors with hot 
soapsuds, or to spray them with gasoline. If the latter method is 
adopted, care must be taken to avoid the possibility of fire. 
To clear a house of fleas Skinner recommends the use of flake 
naphthalene. In a badly infested house he took one room at a time, 
scattering on the floor five pounds of flake naphthalene, and closed 
it for twenty-four hours. It proved to be a perfect and effectual 
remedy and very inexpensive, as the naphthalene could be swept up 
and transferred to other rooms. Dr. Skinner adds, “so far as I am 
concerned, the flea question is solved and if I have further trouble 
I know the remedy. I intend to keep the dog and cat.” 
The late Professor Slingerland very effectively used hydrocyanic 
acid gas fumigation in exterminating fleas in houses. In one case, 
where failure was reported, he found on investigation that the house 
had become thoroughly reinfested from pet cats, which had been left 
untreated. Fumigation with sulphur is likewise efficient. 
The fact that adult fleas are usually to be found on the floor, 
when not on their hosts, was ingeniously taken advantage of by 
Professor S. H. Gage in ridding an animal room at Cornell University 
of the pests. He swathed the legs of a janitor with sticky fly-paper 
and had him walk back and forth in the room. Large numbers of 
the fleas were collected in this manner. 
In some parts of the southern United States hogs are commonly 
infested and in turn infest sheds, bams and even houses. Mr. H. E. 
Vick informs us that it is a common practice to turn sheep into barn- 
lots and sheds in the spring of the year to collect in their wool, the 
fleas which abound in these places after the hogs have been turned 
out. 
It is a common belief that adult fleas are attracted to fresh meat 
and that advantage of this can be taken in trapping them. Various 
workers, notably Mitzman (1910), have shown that there is no basis 
for such a belief. 
The true chiggers — The chigoes, or true chiggers, are the most 
completely parasitic of any of the fleas. Of the dozen or more known 
species, one commonly attacks man. • This is Dermatophilus penetrans, 
more commonly known as Sarcopsylla penetrans or Pulex penetrans. 
This species occurs in Mexico, the West Indies, Central and South 
America. There are no authentic records of its occurrence in the 
United States although,.as Baker has pointed out, there is no reason 
