1 Aprrn, 1899.] QUEENSLAND AGRICULTURAL JOURNAL. 305: 
The result of this exposure was that four of the five cattle which had 
never before been exposed, and which were not protected by inoculation, died 
during June and July. The fifth had a very severe attack and barely escaped 
death. These five animals were used as checks to prove that the inoculated 
animals were exposed to a virulent infection. The four animals which had 
previously been exposed all contracted the disease, but none died. Three were 
very severely affected, and one had a rather mild attack. The nine inoculated 
animals fared very much better. None of these animals died. Five showed 
no symptoms of disease, and the remaining four were affected in a very mild 
form. These animals were again exposed the following summer (1897), after 
which they were sold in good condition. 
This has been the most conclusive experiment that has been made in this 
country, if not in the world, to demonstrate the value of protective inoculation. 
Unfortunately other pressing duties have prevented this line of investigation 
being followed up and fully worked out. While this one experiment would 
seem to indicate that inoculation may be easily and safely performed, and that 
it protects satisfactorily, there might be exceptions in practice. The breed of 
the animal has considerable influence in determining the seriousness of the 
attack. Valueless scrubs probably resist best, while beef breeds would be in 
most danger. What is true of young cattle may not be true of older ones. 
There may also be a difference in the viruleuce of the contagion from 
different sources. The people in some parts of the infected district claim that 
while their cattle resist the native infection they are killed by exposure to: 
cattle which come from some other parts of that district. Again, the Austra- 
lians, who are now inoculating quite largely, think that the blood from an 
animal which has only recently recovered from an attack of the fever produces 
milder disease when used for inoculation than does that of an immune animal 
from the infected district or that of a native which has been sick and recovered 
a long time before the blood is used. : 
These are all points which need to be worked out experimentally before 
inoculation can be practised with safety on valuable cattle purchased for 
breeding purposes. ‘The method is apparently entirely feasible if confined to 
calyes or yearlings, and possibly it may also be used with almost equally 
favourable results with mature cattle. Im the latter case, however, there is 
more doubt, and anyone trying such inoculations should proceed cautiously. 
The writer is quite confident that within a very few years nearly all pure- 
bred cattle taken to the Southern States to improve the stock will first be 
inoculated to preserve them from the dangers of Texas fever. 
TEXAS FEVER PROBLEMS.—V. : 
Although the dipping of cattle from the infected district will remove the 
danger of contagion from them, and although the inoculation of young animals 
destined for the infected district will prevent them from the fatal effects of con- 
tagion, the stockmen of the greater part of that district have something more to 
look forward to, and may indulge the hope that with time and proper efforts their 
section may be entirely relieved of the infection. People now living have seen 
the intection extend itself for many miles, and the probability is that little, if. 
any, of our territory contained the contagion at the time the continent was 
first settled by Europeans. 
We have seen that two parasites are necessary for the production of 
Texas fever under natural conditions. As the tick has been able to accustom 
itself to greater cold, it has gradually extended its habitat to higher latitudes 
and greater altitudes, and in doing so has earried with it the microscopic 
protozoa which constitute the contagion. 
The fact that the fever tick and the protozoa infest South American cattle, 
and that they exist over a wide extent of the African continent and also in 
Australia, would seem to indicate that both parasites had originally been 
brought to America with the settlers’ eattle. It now remains to determine 
whether the protozoa of this disease exist anywhere and multiply otherwisejthan 
