THE EAT PROBLEM 179 



kept well baited all the time, and open. As soon as it is noted 

 that the rats are feeding in it freely, close the trap end and 

 make a catch. 



Poisons are rather " unbiological " and require some care in 

 handling. The Department of Agriculture has recommended 

 barium carbonate as the cheapest and safest poison to use for 

 rats and mice. It is tasteless, and in the small quantities used 

 is not dangerous to domestic animals. Another advantage is 

 that it is slow in acting and the vermin leave the premises to 

 die. Mix oatmeal with one eighth of its. bulk of the poison 

 into a stiff dough with water, and place a teaspoonful in a 



FIG. 87. A good design for a runway trap 



These traps were so poorly made that they were likely to fly to pieces when 



snapped, and never caught a good-sized rat for the author until he had put in a 



row of tack points along the end of the hottom board 



plate about likely places. Or moisten a slice of bread and rub 

 in a quantity of the barium powder on both sides, spreading 

 butter over it ; cut into inch cubes and place in the runways. 

 Or mix two teaspoonfuls of the barium with an egg, thicken 

 to a stiff paste with oatmeal, corn meal, or bread crumbs, and 

 distribute as before. Pieces of raw Hubbard squash with the 

 poison rubbed well into all the cut surfaces, and with cuts 

 made in the flesh and filled with it, make excellent baits. It 

 is well to change the kind of bait and at first to feed freely 

 with the same material unpoisoned, and even then, according 

 to the writer's experience, you will not succeed in fooling the 



