USE OF POISONS FOR DESTROYING NOXIOUS MAMMALS. 427 



CicuTA AND SQUILL. — Tliese two plants have been reconnnended for 

 destroying rats and mice, and published formularies contain direc- 

 tions for preparing the poisons. The first is Cicuta virosa or 

 mmulata^ known as water hemlock, a common marsh plant, the roots 

 of Avhich contain a very active poisonous principle known as cicu- 

 toxin. This produces tetanic convulsions and death in animals. The 

 bulbs of the common squill or sea onion contain scillitin, a poisonous 

 glucoside which dissolves in alcohol or ether. This poison is some- 

 times used in connection with barium carbonate, the squill, it is said, 

 being used chiefly to attract rats or mice to the bait. The writer has 

 not yet tested the efficiency of these poisons. 



POISONING WOLVES AND COYOTES. 



Passing from the general consideration of poisons to their practical 

 use by the farmer and stockman for the 2)rotection of his property 

 against pests, it may be stated that strychnine is the most effective 

 poison known for wolves. The strychnia sulphate is to be preferred 

 on account of its quicker action. The proper dose for a wolf is 4 

 grains ; for a coyote, 2 grains. The common 3-grain gelatin capsules 

 of the drug stores, if well filled, Avill hold 4 grains of strychnine. 

 The 2-grain capsule should be used for coyotes. Fill, cap, and care- 

 fully wipe each capsule to remove every trace of the drug from the 

 outside. Insert it into a piece of beef suet the size of a w^alnut and 

 close the cavity. The baits should be carried in a can or pail and not 

 handled except with gloved hands or forceps. They should be 

 dropped from horseback along trails followed regularly by wolves 

 or along an artificial trail made by dragging an old bone or piece of 

 hide well saturated with the fetid scent described in Circular 63 of 

 the Biological Survey, which should be consulted for more detailed 

 directions for destroying wolves. These baits are very effective when 

 placed around or partly under a carcass on Avhicli wolves or coyotes 

 are feeding. ~ 



POISONING PRAIRIE DOGS. 



Poison and fumigation with carbon bisulphid are the only means 

 that have proved successful in destroying prairie dogs over large 

 areas. The cost of poisoning is less than half the cost of fumiga- 

 tion. The area should first be gone over w^ith poison and the bulk 

 of the animals thus destroyed. The few that escape may then be 

 located in their burrows and destroyed with carbon bisulphid. 



AVlieat treated with strychnine has proved an economical and 

 efficient poison, but is objectionable because it kills numerous valu- 

 able birds. Rolled grain and meal are less likely to be eaten by 



