EXPERIMENTS AGAINST CHICKEN LICE AND DOG ELEA. 



and were applied by rubbing a piece about the size of a pea well into 

 the skin around or below the vent of the infested fowls. This method 

 of treatment has been thoroughly tested by G. H. Lamson and J. A. 

 Manter. 3 The active ingredient here is the mercury, since paraffin 

 or vaseline applied in the same manner is of no value. 



CHICKEN-LICE POWDERS. 



Forty-five of the common proprietary powders generally sold as 

 ."Lice Powder," "Lice Killer," "Lice Exterminator," etc., were 

 tested and, with a few exceptions, were found to be effective if 

 thoroughly applied. These powders are all of the same general type 

 and contain one or more of the following active ingredients: Naph- 

 thalene, nicotine, sulphur, pyrethrum, or phenols, and are mixed 

 with lime, sand, talc, fuller's earth, or diatomaceous earth as a 

 filler or carrier. Most of these active ingredients have been tested 

 separately, and the niinimum. amounts that will be completely 

 effective when very carefully and thoroughly applied by experienced 

 persons are as follows: Naphthalene 10 per cent, nicotine 0.75 per cent, 

 sulphur 20 per cent(?), pyrethrum 5 per cent, phenols 15 per cent (?). 



In some of these powders the actual percentage of one or even all 

 of the active ingredients fell below the minima given above, but the 

 combined action of all of the active ingredients was sufficient to make 

 the preparation effective. 



MISCELLANEOUS PREPARATIONS. 



In two tests, in which powders containing nicotine, naphthalene, 

 and sulphur were added to the dust baths furnished to lousy hens, 

 95 to 100 per cent of the lice were killed. This method of treatment 

 is not, however, a very practical one, since all fowls do not dust 

 themselves and the few that do not will eventually reinfest the whole 

 flock. 



Nicotine, if used at a reasonable strength, was found to be effective 

 as a dip or spray. 



Lime-sulphur added to the drinking water (1 teaspoonful to a 

 gallon), and a powder composed of sulphur, salt, sodium carbonate, 

 naphthalene, charcoal, and lime, which was given with the food, were 

 found to be absolutely without any effect on the lice. 



PYRETHRUM POWDER.* 



In a series of 12 tests pyrethrum powder (insect powder, Dalma- 

 tian insect powder, or Persian insect powder) was found to be very 

 effective, killing all of the lice within 24 hours. In dilution tests it 

 was found that a powder containing 5 per cent of pyrethrum was 

 effective if very thoroughly and carefully applied. 



2 Lamson, G. H., jr., and Manter, J. A. Some lice and mites of the hen. Storrs Agr. Exp. Sta.,Storrs, 

 Conn., Bui. 86. 1916. R 



3 Powdered flower heads of Pyrethrum cinerariaefolium and P. roseum. 



