146 Annual Report for 1905 of Royal Veterinary College. 
years would leave no living ticks on the ground. To exclude 
animals from even a single field for two years would of course 
entail a considerable loss even in the most favourable circum- 
stances, but fortunately it would only be necessary to exclude 
cattle. None of the other farm animals can be infected with red- 
water, and there is therefore no reason why the worst-infected 
pastures should not be grazed by horses or sheep. It is true 
that this would not lead to extermination of the ticks, for these 
attach themselves to other animals than cattle, but even when 
an infected tick attaches itself to a sheep or horse the progeny 
of that tick are free from infection, and therefore harmless for 
cattle. 
From what has just been said, it will be inferred that, when 
experience has shown that on any farm cases of redwater 
occur only on a particular part of it, an effort should be made 
to exclude cattle from that for at least an entire year, and if 
possible for two years. 
When a case of redwater occurs, the affected animal ought 
to be immediately housed ; and, in the event of its recovery, it 
ought to be kept indoors for not less than three weeks. The 
motive for this is to prevent the ticks on it from escaping on to 
pasture, and during the period of its isolation its skin ought to 
be searched for ticks. It is scarcely possible to detach these 
until they do so voluntarily, and then they ought to be collected 
and destroyed. Even if no ticks are detected, the litter and 
manure ought to be carefully removed, and either burnt or 
stored until it can be applied to ploughed land. After the 
three weeks have elapsed, the recovered animal ought not to be 
returned to the infected pasture, but if possible put to grass on 
a field subject to rotation of crops. 
If it is impossible to exclude cattle from what is known to 
be infected pasture, then it is well to remember that bought-in 
cattle, assuming that they come from a healthy farm, are* 
more likely to contract the disease than those bred and reared 
on the place. Known infected pastures, if they must be grazed 
by cattle, ought therefore to be reserved for home-bred animals, 
and the younger these are the less will be the risk. 
In concluding the subject of prevention it may be 
mentioned that cattle may, with a certain amount of risk, 
be immunised or vaccinated against redwater. It has been 
previously explained that the blood of recovered cattle generally 
continues to harbour small numbers of the redwater parasites 
for a long time afterwards, and inoculation with the blood of 
such recovered animals almost invariably excites an attack 
of redwater in a healthy subject. Sometimes, however, the 
attack which is thus set up is of a very mild character, but 
sufficient to confer protection against subsequent infection 
