THE PRAIRIE DOG OF THE GREAT PLAINS. 2G7 
towns, is ^1.50 to >$'Ji per ounce. It comes in l-dniiu (^-oiincc) bottles 
which usually retail for 25 cents. Assuming- that 2 ounces is the 
quantity necessary to poison a bushel of grain, the poisoned grain 
would cost about ^5 per bushel. Allowing a tablespoonful to ]ni the 
average quantity necessary to scatter about each hole, and allowing 50 
holes to the acre,^ a bushel of grain will poison 40 acres, at a cost of 
12i cents per acre. A man can scatter poisoned grain over 50 acres 
or more per day; hence, if labor costs 9^1 per day, the expense per 
acre of putting out the poison would be 2 cents, Avhich added to the 
above 12^ cents for materials, makes the total cost 14i cents per acre. 
The first application of the poison, if carefully made in late winter or 
early spring when food is scarce, may be counted on to kill 75 to 80 
per cent of the animals (and has been know^n to kill as high as 95 per 
cent), and this at a cost per acre of less than 15 cents. The second 
application, a week or two later, is aimed at the few remaining occu- 
pied holes, which sl^uld not average more than two or three to the 
acre, and the cost per acre should not exceed 1, or at most, 2 cents. 
If any animals remain, they may be killed by bisulphide of carbon, 
and in many cases it is better to do away with the second poisoning and 
use bisulphide to kill oft those that are left after the first poisoning. 
FUMIGATION. 
By fumigation is meant the destruction of animals by fumes arising* 
from substances thrown into the burrows, as bisulphide of carbon, or 
generated outside and forced in by mechanical appliances known as 
f umigators." Fumigators are devices b}^ means of which fumes from 
burning sulphur or other materials are pumped into the burrows. In 
parts of the West, particularh^ California, they have been used wilh 
success in killing gophers and ground squirrels. They have been siu - 
cessfully used also against prairie dogs, but their employment for tliis 
purpose does not appear to be gaining ground. 
Bisulphide of carbon. — Bisulphide of carbon is a volatile liiiuid 
which rapidly loses its strength on exposure to the air, and should be 
kept in tightly corked bottles or cans, which, when used, should l>e 
immediately recorked. It is infiammable and highly oxplosiv(\ and 
should never ])e opened in the vicinity of a light or fire. Its fumes 
are heavier than atmospheric air, and when introduced into burrows 
sink ([uickly to the bottom. 
The nu'thod of application is exceedingly simple. Th(» u>ual dcv^e 
for prairie dogs is 1 ounce (about a tabU^spoonf ul). Tliis ijuantity 
should be poured on some absorbent substaiun*. such as a Uinip of hor^e 
manure, a corncob, a handful of rags, or even a clod of earth, which 
^ A large average, but made to include iinoecupied holes, as it is inueii cheaper to 
put out a little extra grain than to i>lug the holes to find out which are occupied. 
Furthermore, grain scattered anywhere in the dog towns is liable to be eaten. 
