36 THE ROCKY MOUNTAIN SPOTTED FEVER TICK. 
IMPORTANCE OF CONTROL THROUGHOUT THE BITTER ROOT VALLEY. 
For several reasons it is necessary to carry on this plan of eradica- 
tion on both sides of the valley. It is known that the fever is very 
much less prevalent on the east than on the west side. This situation, 
however, is undoubtedly in part due to the heavier population on the 
west side and the greatersnumber of live stock. There is every 
reason to believe that the settlement of the east side, with the in- 
evitable increase in the number of live stock and, consequently, of 
opportunities for the ticks to breed to maturity, would result in an 
increased number of cases of spotted fever. That this is not a re- 
mote danger is shown by the fact that the development of the east 
side has already begun and will undoubtedly continue with rapidity. 
We do not wish to be understood as believing that the comparatively 
unsettled condition of the east side is the only reason for the scarcity 
of ticks. There are undoubtedly others. Among these is the greater 
abundance of rodent hosts for the immature stages of the tick on the 
west side. This is due primarily to the larger amount of protection 
in the brush or “slashings,” although the settlement of the land and 
the planting oz crops may have tended, by furnishing food, toward 
the multiplication of the rodents. Soil conditions may also have 
something to do with the difference. 
The main point, however, is that the comparative immunity of the 
east side is not likely to continue. Destroying the ticks on both sides 
would cost but little more than on one. It would prevent the rein- 
festation of the west side. If it were not done, it would be necessary 
to establish and to maintain a quarantine against live stock on the 
east side. From every point of view it is wise to conduct a thorough 
work and clear both sides of the valley at the same time. 
METHODS OF DESTROYING TICKS. 
The two methods of eradicating ticks which will be found to be 
adapted to the conditions of the Bitter Root Valley are (1) the 
dipping of live stock in vats provided for the purpose, and (2) the 
hand treatment of such animals as can not conveniently be dipped. 
In the case of the tick (Margaropus annulatus Say) which trans- 
mits splenetic fever of cattle, a third method has been found to be of 
great importance. This is the elimination of the ticks from pastures 
by “starving” them. This is accomplished by keeping the cattle out. 
During the warm portions of the year, at least, only a few months 
time without hosts will result in the death of the cattle ticks. Im- 
portant differences between the life history of the splenetic-fever tick 
and that of the spotted-fever tick make that plan entirely imprac- 
ticable in the case of the latter species. The problem of the splenetic- 
fever tick is not complicated by the existence of different hosts for 
the immature and the adult stages. That tick is absolutely depend- 
