PREVENTIVE MEASURES 
179 
in the following way: “Macerate during twenty-four 
hours 1,000 parts of quassia wood with 5,000 parts 
of water, then boil for half an hour; set aside for 
twenty-four hours and press. Mix the liquid with 150 
parts of molasses, and evaporate to 200 parts. A 
weaker decoction of the quassia does not kill the flies. 
From this the fly water or fly plate is prepared as fol¬ 
lows: Mix when needed and dispense without filter¬ 
ing, 200 parts of syrup of quassia, fifty parts of alcohol 
and 750 parts of water. It is used by moistening with 
the mixture a cloth or filtering paper on a plate.” 
The native ore of speiss cobalt is found in commerce 
under the name of flystone, and was at one time ex¬ 
tensively used for poisoning flies by roughly grinding 
it and putting a small quantity in a saucer with sweet¬ 
ened water. 
It is possible to poison flies rather satisfactorily by 
putting a lump of sugar in a saucer partly filled with 
water and adding white arsenic. This, of course, is 
dangerous where there are children or house dogs or 
cats about. 
Of the unpatented fly traps, a device was recom¬ 
mended by Mr. P. J. Parrott, Entomologist of the 
Kansas Experiment Station, in Bulletin 99 of the Sta¬ 
tion (October, 1900), as follows: 
“The department of entomology, after experimenting 
upon various mechanical devices for catching flies, has 
contrived a trap and recommended it for trial on ac¬ 
count of its effectiveness and cheapness. Anybody 
with an average amount of mechanical ingenuity can 
