164 PRINCIPLES AND PRACTICE OF MILK HYGIENE 



load lots at the present time, but if a demand is created it will 

 no doubt be available in smaller quantities. In the commercial 

 fertilizers it is usually converted into urea, ammonia, etc. Of 

 the various substances tested, the most satisfactory results were 

 obtained with powdered hellebore and borax. One-half pound 

 of powdered hellebore is mixed with 10 gallons of water and 

 allowed to stand 24 hours. This quantity is sufficient to treat 

 10 cubic feet (8 bushels) of manure, being applied with a 

 sprinkler. The borax is applied with a flour-sifter, especially 

 around the edges of the manure heap, and water is then sprinkled 

 over it; about 1 ounce of borax and 2% to 3 quarts of water 

 are used to each cubic foot of manure. Floors, crevices, and refuse 

 may be treated in the same manner with either hellebore or borax. 

 Borax is perhaps a little more effective as a larvaecide than 

 hellebore, but the latter is not at all injurious to the manure nor 

 to crops while borax in excessive quantity interferes with plant 

 growth. Manure treated with borax as above may be applied 

 in any quantity up to 15 tons per acre without injuring the 

 crops, except in the case of leguminous plants. When borax- 

 treated manure is used to grow leguminous plants, it should be 

 mixed with untreated manure. The effect of the repeated appli- 

 cation of borax-treated manure has not been determined. The 

 cost of treating manure with powdered hellebore is a little over 

 % cent per bushel, while the expense of the borax treatment 

 is a little less than % cent per bushel. 



The cow-fly or horn-fly lays its eggs in fresh cow manure. 

 The larvae are hatched in 24 hours and develop into pupae in 5 

 days. The pupae burrow into the ground and flies emerge in 8 

 days, the time from the egg to the fly being 14 days. 



These flies feed upon the blood of the cow and are therefore 

 not likely to get into the milk or milk vessels. In biting through 

 the skin of the cow to obtain food, they cause the animal con- 

 siderable discomfort. When driven off the body of the cow, they 

 fly only a short distance away and then immediately return, so 

 that, while feeding, they are a continual torment. 



Fly repellents are used to protect the cow from the attacks 

 of these insects. A mixture of one part of oil of tar and nine 

 parts of cotton-seed oil or crude Beaumont oil, applied daily 



