783 
REPORT OF THE COMMITTEE ON DISEASE. 
:ounties in the northern half of the State. In some cases 
hese outbreaks can be traced to importations of cattle from 
adjacent counties, while in other cases it is the imported 
cattle which die while the natives remain unaffected. In many 
larts of the State the movement of cattle for distances of less 
han twenty miles is attended with danger during the summer 
nonths. In explanation of these facts we have to assume 
hat even within districts far within that known as the ‘Texas 
fever Belt’ there are numerous isolated tracts of uninfected 
*anges in which the cattle do not possess immunity against 
;he disease. In these localities cattle ticks sometimes appear 
is numerous as in the infected regions around. In July of 
:his year about two hundred cattle died in St. Francis County 
Df this State. On the prairies on which they died the ticks 
ire not at all abundant, most of the cattle being quite free 
irom them. -The owners report that those which died were 
3ften free from ticks, and in my own inspection I was unable 
to find them. I think it is likely that one or more species of small 
Hies which are exceedingly troublesome to cattle in these districts 
may be concerned in the propagation of the disease. Other species 
of animal life may also act as intermediate bearers of the virus, 
and there is no evidence to show that this is not also con¬ 
tained in the water and soil of infected ranges, and taken into 
the system by ingestion or inhalation, as it is believed to be 
the case with malarial fevers of man. The tick method 
of natural infection is the only one which has been experi¬ 
mentally demonstrated, and on account of the peculiar habits 
and life-history of this parasite is, as we have seen, the agent 
by which the virus is carried to long distances and trans¬ 
ferred to the bodies of other susceptible cattle. Other inter¬ 
mediate bearers which may exist in the regions in which 
Texas fever is endemic are probably confined to these regions, 
or accompany the movements of cattle for only short distances. 
“ Since the discovery of the tick method of infection, I have 
always advised that imported cattle be kept free from these 
parasites during the summer months, but have no data to 
show that this has been instrumental in preventing the disease. 
.Accurate experiments, so far as I am aware, have not yet been 
