POISONING AND TRAPPING = 289 
stroying rodent pests,’’ and as insecticides and 
other poisons for the entire country cost many 
millions of dollars annually, the saving of waste 
in this item of agricultural expense is seen to 
be important. 
Probably the buyer of proprietary poisons 
has the greatest cause for complaint. Often 
one or two cents’ worth of material is retailed 
at from 25 cents to a dollar. The difference be- 
tween the cost of the material and the selling 
price represents the manufacturer’s profit and — 
the retailer’s profit. Such large returns enable 
proprietors to spend much money in advertis- 
ing or otherwise exploiting their wares, which, 
if not worthless, are never so good as an intel- 
ligent man may compound for himself at a 
small fraction of their price. It is to enable 
the readers of this book to do so that the in- 
structions which follow are here given. They 
are formulas which have been dictated by scien- 
tific knowledge and approved by experience; 
and the methods of application recommended 
are those which have been found to involve the 
least possible danger to man, to domestic stock, 
and to valuable wild‘birds and mammals. It . 
