Since the larvæ of fleas are very susceptible to exposure, the use of bare floors, with few rugs, instead of carpets or matting, is to be recommended. Thorough sweeping, so as to allow no accumulation of dust in cracks and crevices will prove efficient. If a house is once 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, barns 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 why it should not become established in Florida and Texas. It is usually believed that Brazil was its original home. Sometime about the middle of the nineteenth century it was introduced into West Africa and has spread across that continent.