) 
worms, which are attracted by the wound left when the tick detaches 
itself or by the blood released when one happens to be crushed on the 
host. 
It will be noted that fully engorged specimens of the fever tick have 
now been found on sheep by Mr. Mitchell in three different flocks in as 
many counties in southern Texas. It is expected that future observa- 
tions will show a rather general occurrence on sheep. 
There are several points of importance to be determined, as, for 
instance, whether the offspring of the ticks which have developed on 
sheep transmit splenetic fever when placed on nonimmune cattle, and 
whether the sheep become diseased through the agency of the ticks. It 
is expected that the Bureau of Animal Industry will undertake investi- 
gations in the near future bearing on these points. The purpose of this 
circular is merely to call attention to matters of immediate practical 
importance. 
It may possibly be important to note that there are some peculiar 
features of the cattle-tick problem in southern Texas this season. 
Various conditions have caused unusually large numbers of ticks to be 
present in the spring. According to the testimony of cattlemen the 
ticks have never been more abundant in the spring than they are this 
season. It is barely possible that this excessive abundance may have 
had something to do with the occurrence of ticks on sheep, and that 
under different conditions the sheep would not have become infested. 
Nevertheless, it must be remembered that in that portion of Texas as 
well as elsewhere the cattle ticks are frequently as numerous in the fall 
of the year as they have been this spring. In view of these facts it seems 
evident that it will be absolutely necessary in plans for eradication to 
exclude sheep from areas in which an attempt is being made to eradi- 
cate the ticks. 
Approved : 
JAMES WILSON, 
Secretary of Agriculture. 
WASHINGTON, D. C., June 19, 1907. 
O 
