Redwater in Cattle. 
147 
by ticks. Unfortunately, the exceptions to this rule are con- 
siderable, and they can never be foreseen. Some experiments 
in this direction have been carried out at the Royal Veterinary 
College during the past two years, and out of ten cattle 
experimentally infected with redwater only one died, and that 
one was at the time affected with another disease which 
certainly contributed to its death. Only one of the remaining 
nine animals had an attack which endangered its life ; in 
another the attack was moderately severe but not dangerous, 
and in the other seven there was scarcely any appreciable 
disturbance of the general health. 
,|o As has already been stated, redwater is mainly a disease of 
summer and autumn, but attacks of acute illness characterised 
by all the chief symptoms of this disease, including the 
abnormal appearance of the urine, are sometimes observed in 
cows during the months of winter or spring, at a time when 
the animals are confined to the house, and when tick infection 
is scarcely possible even among cattle at grass. It cannot be 
said that the identity of these attacks with the redwater 
described above has been proved ; but, in spite of the different 
conditions under which they occur, it is quite possible that the 
two diseases are the same. 
It is well known that animals which contract the disease 
and recover while at pasture in summer or autumn may have 
a relapse or second attack afterwards, and this is especially 
likely to happen if from almost any cause the animal’s general 
health becomes seriously depressed. The winter attacks of 
redwater are generally seen among recently calved cows, and it 
is possible that they are of the nature of relapses brought on 
by the general disturbance and drain on the system incidental 
to parturition. 
J. McFadyean. 
Koyal Veterinary College, Camden Town. 
