Mites and Lice on Poultry. 21 



Since there is very little danger of reinfestation from lice on molted^ 

 feathers, the question of avoiding the moltmg period is not a serious 

 one, yet, if the treatment can precede molting it probably would be 

 better. 



If the fall treatment has been neglected it is imperative that the 

 flock be cleaned of lice before brooding time in the spring. Usually 

 this would mean that the dusting method would have to be followed 

 on account of adverse weather conditions. Treating the birds at 

 this time will insure their vigor as well as undisturbed broodmg, 

 which is necessary to successful hatching, and, what is more important, 

 the infestation of the young chickens will be avoided. Although lice 

 normally stay upon the host continuously and do not have the habit 

 of hiding away in cracks about buildmgs, yet the poultry houses 

 and runs should be well disinfected occasionally, especially as action 

 against mites is necessary if these are present. It is well to make 

 this general clean-up at the time the flock is treated for lice. This 

 minimizes any danger of reinfestation. 



On large poultry farms the complete eradication of lice is often 

 complicated by inabihty to control the fowls. When proper pen 

 construction is at hand, it is possible to treat a pen or two a day until 

 the entire flock is covered. The more rapidly treatment progresses 

 the better, of course, and great care should be taken to avoid the 

 escape of fowls from infested to uninfested pens. 



SODIUM FLUORID EFFECTIVE AGAINST ALL LICE. 



The writers have tested a number of the materials most generally 

 advocated for lice destruction and several new compounds which it 

 was thought might be effective. In this series of tests nothing else 

 was found to be as satisfactory as sodium fluorid. The experiments 

 have demonstrated that this chemical is exceedingly poisonous to 

 all species of chicken hce. It kills both adults and young, including 

 the young which emerge from the eggs present at the tiflie of treat- 

 ment. 



Sodium fluorid can be obtained in two forms, known as cormnercial 

 and as chemically pure. Both of these are in a dry state, the former 

 being a dry powder and the latter consisting of small crystals some- 

 what lumpy. While the chemically pure material is effective, it is 

 not as easily apphed by the dusting method as the more finely pow- 

 dered commercial form, and, furthermore, it is higher in price. The 

 commercial grade should contain 90 to 98 per cent sodium fluorid. 



This material is the sodium salt of the chemical element known as 

 fluorin and hence is a compound very similar to ordinary table salt, 

 wliich is known chemically as sodium chlorid. In asking for sodium 

 fluorid it is therefore important that the name "fluorid" be carefully 

 stated to the druggist. Up to this time the demand for the material 



