71 



but the precipitated barium carbonate (which is best) should be 

 kept in stock by all leading wholesale druggists. It is an old 

 and well-known rat poison, which apparently has been used 

 with good results by many people. 



Directions for Use of Poison in Poultry Houses. — No poison 

 was used in poultry houses in the experiments made by the 

 Massachusetts State Board of Agriculture, as the owners were 

 not anxious to take the risk, several having already poisoned 

 fowls. I cannot recommend anything but rat-proofing for 

 poultry houses, but the Biological Survey recommends the 

 following plan : — 



Two wooden boxes should be used, one considerably larger than the 

 other, and each having two or more holes in the sides large enough to 

 admit rats. The poisoned bait should be placed on the bottom and near 

 the middle of the larger box, and the smaller box should then be inverted 

 over it. Rats thus have free access to the bait, but fowls are excluded. * 



If strychnine is used the poisoned rats may not be able to 

 get out of the box, or if they leave it they may not get to their 

 holes and may be picked up in the morning and buried to pre- 

 vent other animals from being poisoned by eating them. There 

 is always an element of danger, however, in using poison in a 

 poultry house, as rats may carry out poisoned food and leave 

 it where the fowls can get it. Mice when poisoned with 

 strychnine are rarely able to leave such a box, and so may be 

 poisoned in the house without much danger of disagreeable 

 results. 



General Directions for Poisoning. — Care should be taken in 

 mixing and putting out poisons not to handle them or the food 

 in which they are mixed unless scents are used on the hands, 

 as in the directions for trapping given on page 45. Where rats 

 seem suspicious of poisons it is best to put out unpoisoned 

 material, such as that in which the poison is to be mixed, until 

 the rats have become accustomed to eat it nightly. Then 

 deprive them of it for one night and give them poisoned food 

 the next. Poison should never be left out of doors where birds 

 or domestic animals are likely to get it. If put in rat holes it 

 should be inserted well in with a long-handled spoon. Poisoned 



' Lantz, David E., U. S. Dept. Agr., Fanners' Bulletin 297, 1907, p. 5. 



