26 



SPERMOPHILES OF THE MISSISSIPPI VALLEY. 



used to advantage, as shown by the practical experience of Mr. Roll in 

 C. Cooper, of Oooperstown, N. Dak. He writes, under date of Novem- 

 ber 28, 1888: 



" I am farming 7.000 acres, and the gopher question has been one of 

 great interest to me. I now think that I have the best of them and can 

 rid my farm of them at little expense. I send men overmy fields about 

 twice in the spring, the first time as soon as the animals commence 

 coming out of their holes, with wheat soaked in strychnine water. I use 

 one ounce of floured strychnine to each bushel of wheat. Every farmer 

 can Hour his own strychnine with a caseknife on any piece of iron or 

 glass: it should then be put into quite warm water, dissolving the 

 strychnine fully. Pour on water until the wheat is nicely covered, let- 

 ting it stand the necessary time. Soak the wheat twenty-four to thirty- 

 six hours, or until somewhat soft. When sufficiently soaked each man 

 takes a teaspoon and a small can and walks over the fields, putting one 

 tea spoonful into each hole. This being carefully done a couple of times 

 each year will soon clean the animals out, and will greatly repay the 

 farmer, even if repeated every year, as one man can go over 50 to 100 

 acres per day." 



Under this head should be mentioned the numerous brands of squir- 

 rel poison or squirrel exterminators which have been put on the 

 market during recent years. These consist of grarn, usually wheat, 

 prepared with strychnine or other poison ready for use. The different 

 brands have proved of varying value, but several of them have been 

 highly recommended, and in use have proved eminently successful as 

 well as economical. 



Bisulphide of carbon. — One of the simplest means and probably 

 the most effective and cheapest method yet devised for destroying 

 these animals is by the use of bisulphide of carbon. This compound 

 when pure forms a colorless, mobile liquid having a peculiar odor, and 

 when taken internally is a violent poison. As usually obtained it con- 

 tains impurities in the form of other compounds of sulphur which give 

 it a strong and extremely offensive odor, and when inhaled it soon causes 

 death. For the purpose of destroying gophers or ground squirrels the 

 crude bisulphide is better and much cheaper than the pure article. Care 

 should be taken in using the liquid, as it is both inflammable and explo- 

 sive. Its efficacy depends on the fact that its vapor is heavier than air 

 and when introduced into burrows flows like water into ail the recesses. 

 This should be borne in mind in using it on sloping ground or in places 

 where there is reason to suppose that the holes contain water, for un- 

 less the poison is introduced at the highest opening of the burrow a 

 certain part of the hole will remain free from it and here the animals 

 may take refuge. If the holes contain water, this may act as a water 

 trap preventing the diffusion of the vapor. 



The method of use for burrowing mammals is as follows: A small 

 quantity (about 45 cubic centimeters or 3 tablespoonfuls for prairie 



