38 



CIRCULAR 148, U. S, DEPARTMENT OF AGRICULTURE 



apart, in either of these clips can usually be depended on to eliminate 

 horse lice. Two dippings in nicotine solution will ordinarily free 

 horses from lice. On account of the difficulties in dipping in cold 

 weather, and the unsatisfactory nature of hand treatments, most of 

 them only palliative, it is advisable to dip for lice, when they are 

 present, in the fall of the year before the onset of cold weather. 



Hand applications of dusting powders and oils and greases are 

 often resorted to in treating horses for lice. Some of the dusting 



powders are of value 

 in holding the para- 

 sites in check, but. as 

 a rule, they are not 

 effective in controlling 

 sucking lice. Biting 

 lice can be destroyed 

 with sodium flouride 

 applied in the form of 

 a powder or mixed 

 with water in the pro- 

 portion of about 1 

 ounce to 1 gallon; but 

 sodium fluoride is not 

 effective against suck- 

 ing lice. Care should 

 be taken not to apply 

 sodium fluoride too 

 freely around the nat- 

 ural body openings 

 or where the skin is 

 very thin and hairless, 

 and not to rub it into 

 the skin. It may be 

 applied with a dust 

 gun, or a shaker, or 

 by hand. 



Oils and greases, 

 such as crude petro- 

 leum, crank-case oils, 

 or equal parts of cot- 

 tonseed oil and kero- 

 sene are effective 

 nee. Eyes remedies for lice; but 

 as. Part of ordinarily they are not 

 suitable for use on 

 and they often blister 



Figure 26. — Fumigation with sulphur gas f' 

 and nostrils must be kept away from the 

 head not fumigated must be hand treated 



horses, as they cause the hair to come out 

 the skin. 



Fumigating horses with the fumes from burning sulphur (sulphur 

 dioxide) will kill horse lice, but many of the eggs survive, and two 

 treatments two weeks apart are necessary to effect eradication. The 

 advantage of this method of treatment is that it can be used when 

 the weather is too cold for dipping. The disadvantages are that it 

 is necessary to have a gas-tight inclosure and the animal's eyes and 



