CONVICT LABOR FOR ROAD WORK. 105 
It has been found that a single fly may carry more than 6,000,000 
germs on the outside of its body and as many as 28,000,000 in its 
intestinal canal. What it means, therefore, to have a fly fall into 
milk or other liquid food is seen readily. 
The suppression of flies at convict camps can be successfully ac- 
complished only by doing away with their breeding places. Screens, 
flytraps, sticky fly paper, and poisons all are useful in waging war 
against them but are not, in themselves, sufficient. The fundamental 
rule which should be enforced rigidly is that of absolute cleanliness of 
the camp and its surroundings. Human excreta, garbage, and other 
wastes must be protected from flies by methods described under para- 
graphs dealing with those subjects, and such breeding places as 
stables, chicken yards, and hogpens should be removed as far as 
possible from the main structures. As flies seldom travel more than 
500 yards from their breeding places, it follows that if the mess and 
living quarters be separated from such places by at least that dis- 
tance immunity from flies will be practically assured. But it is usu- 
ally impracticable to locate the stable at such a remote distance, and, 
since piles of manure are favorite breeding places, special measures 
must be adopted for their disposal or treatment. The most practical 
of such measures are outlined as follows: 
(1) The manure may be placed in covered barrels each morning 
for removal by farmers at least twice a week, and the polluted 
ground about corrals may be sprinkled with kerosene; (2) the 
manure may be burned in an incinerator; (3) the borax treatment: 
Apply 0.62 pound borax, or 0.75 pound calcined colemanite, to every 
10 cubic feet (8 bushels) of manure immediately on its removal from 
the barn. Apply the borax with a flour sifter or any fine sieve, par- 
ticularly around the outer edges of the pile, and sprinkle 2 or 3 gallons 
of water over the borax- treated manure. 1 With regard to the effect 
of this treatment upon the value of the manure as a fertilizer, it is 
recommended that not more than 15 tons of the borax-treated 
manure be applied to an acre, as its effect has not been studied in 
connection with all crops. With borax at from 5 to 6 cents per 
pound the cost of the treatment will be about 1 cent per horse per 
day, and if calcined colemanite be purchased in large quantities 
the cost should be considerably less; (4) the hellebore treatment: 
Apply to every 10 cubic feet (8 bushels) of manure a mixture of one- 
half pound of powdered hellebore in 10 gallons of water. As in the 
case of the borax treatment, special attention should be given to 
the outer edges of the pile. This treatment is somewhat more expen- 
sive than the borax treatment, the estimated cost per horse per day 
I 
1 Bulletin No. 118, U. S. Department of Agriculture: "Experiments in the Destruction of Fly Larva? 
in Horse Manure." Bulletin No. 245, " Further Experiments in the Destruction of Fly Larvae in Horse 
Manure." 
