24 Farmers' Bulletin 801. 



injure the skin of the fowl and give the feathers a thorough wetting. 

 The experience of the writers does not justify this aversion when dip- 

 ping in a sodium-fluorid solution. It may be said that in general the 

 dipping method is most applicable to the Southern States and to sum- 

 mer treatments in the north. The first requisite is a rather warm 

 sunny day, so that the fowls will dry quickly. Windy weather should 

 be avoided. In dipping fowls as described below, the feathers do not 

 get thoroughly wet, and if the operation is finished an hour before 

 sundoAvn the fowls wiU become thoroughly dry before going to roost. 

 In rather extensive tests of this method the writers have observed 

 no iU effect whatever from the dipping. As compared with dusting, 

 this method has an advantage in that it reduces considerably the 

 cost of materials, is more rapidly done, and the discomfiture to the 

 operator is avoided. It is just as effective as dusting. 



The lice die much more quickly following dipping than when 

 sodium fluorid is applied in dust form. It appears that all those 

 which are touched by the liquid die very promptly, and the others 

 succumb in a few hours. 



In using the dipping method all that is necessary is a supply of 

 tepid water and a tub. If two persons are to dip at the same time 

 it is advisable to use a large tub. The water should be measured 

 into the tub and three-fourths to 1 ounce of commercial or two- 

 thirds of an ounce of chemically pure sodium fluorid added to each 

 gaUon of water. It is readily dissolved by stirring. The tub should 

 be filled to within 6 or 8 inches of the top, and as the amount of 

 solution is lowered through dipping numbers of fowls, water with 

 the proper proportion of sodium fluorid dissolved should be added 

 from time to time. In dipping the fowls it is best to hold the wings 

 over the back with the left hand and quickly submerge the fowl in 

 the solution, leaving the head out wliile the feathers are thoroughly 

 ruffled with the other hand so as to allow the solution to penetrate 

 to the skin on different parts of the bird. The head is then ducked 

 once or twice, the bird is lifted out of the bath and allowed to drain 

 a few seconds and is then released. 



It is not necessary to keep the fowl under the water longer than 20 

 to 30 seconds and the head only an instant. 



Owing to the fact that pigeons are so closely feathered it is necessary 

 to add about three-fourths to one ounce of laundry soap to each gal- 

 lon of water in order to increase the penetration of the dip. A 

 thorough dipping of the pigeons in this way, ruffling the feathers 

 while the birds are under the water, will destroy all lice. 



EFFECT OF SODIUM FLUORID ON FOWLS AND MAN. 



Fortunately this compound is very destructive to lice without 

 producing any ill effects on the chickens. No skin irritation or 

 injury to the condition of the feathers has been observed in the large 



