14 BULLETIN 888, U. S. DEPARTMENT OF AGRICULTURE. 



In tests Nos. 1 and 2 the interior of a box about 3 feet long, 2 feet 

 wide, and 2 feet deep was thoroughly painted or sprayed, and a small 

 dog was placed in the box, which was then covered with two or three 

 thicknesses of burlap. This method of treatment produced a true 

 fumigation, since the dogs in every case remained standing during 

 the entire experiment. When the dogs were taken from the boxes 

 examination showed no living fleas on them, and it is evident that 

 the insects had been killed by the vapors arising from the sprays 

 used. This view is supported by the results of a long series of tests 

 of a similar nature, in which various oil preparations were found to 

 be effective against chicken lice. (See p. 3-4.) 



In tests Nos. 3,4, and 5 the materials were lightly sprayed on a 

 blanket or old sack, and this was tightly wrapped about the dog so 

 that only the face and legs remained uncovered. This method of 

 application gave, in addition to the fumigation effect, a very probable 

 contact effect, since some of the oils would naturally pass from the 

 blanket to the hair of the dog, and any fleas coming to the surface 

 of the hair would come in contact with the sprayed blanket. This 

 treatment was also very effective, as no living fleas were found on 

 dogs that had been covered with the sprayed blankets for two hours. 



SUMMARY. 



1. Pyrethrum powder alone or when it formed not less than 50 per 

 cent of a mixed powder was very effective, but pyrethrum stems were 

 of no value. 



2. Pure naphthalene was found to be effective if well rubbed into 

 the hair. 



3. Twenty-one lice powders were more or less effective, depending 

 on the amount of active ingredients present and the fineness of the 

 powder. 



4. A powder containing 18 per cent of sassafras oil was effective, 

 and powders containing 10 per cent or less of other oils were of no 

 value. 



5. Cloves, naphthalene^ paradichlorobenzene, and sassafras bark 

 were effective against fleas and 21 powdered substances were of no 

 value. 



6. Tobacco powders containing over 1 per cent of nicotine were of 

 some value against fleas, but a powder containing as high as 4.56 per 

 cent was not completely effective. 



7. The emulsified disinfectants were found to be effective as sprays 

 at the rate of 1 part to 64 parts of water and as washes and dips at 

 1 to 130. 



8. Several liquids used as fumigants were found to be effective 

 against fleas. 



