144 Annual Report for 1905 of Royal Veterinary College. 
the most deadly certainty. To effect this it is merely necessary 
to take a few drops of the warm fresh blood of a redwater 
animal and inject it into the one which it is desired to infect. 
After a time which varies with the amount of blood used for 
the experiment (usually about a week when only a small 
quantity has been used), the inoculated animal sickens and 
begins to pass red urine. Needless to say, this result is 
attributable, not to the injection of the blood itself, but to the 
redwater parasites present in it. 
But, as previously stated, redwater is not naturally a disease 
which spreads by contagion, and it remains to explain how, 
in natural circumstances, the parasites which are the cause of 
it find their way into the body. This really great discovery 
was made by two American authorities (Smith and Kilborne), 
who proved what had previously been suspected, viz., that 
cattle are infected with redwater by the agency of a tick. In 
the case of the redwater of the United States, Africa, and 
Australia, the tick which plays this part has been identified, 
and it is known that the females which have sucked the blood 
of an infected animal produce a brood of ticks capable of 
conveying the disease to the cattle to which they become 
attached. The redwater parasites (or piroplasms, as they are 
named) are thus handed on from the mother tick to her 
offspring, but as yet all attempts to identify them either in the 
mother tick, eggs, or young ticks have failed. The ticks thus 
do in a round-about way what one can do directly with a 
hypodermic syringe, using the latter to draw off a little blood 
from a diseased animal and immediately injecting it into a 
healthy one. 
There is not the least doubt that European redwater is 
identical with the redwater of the other Continents in the 
sense that it is caused by piroplasms in the blood, and there 
is also no room to doubt that it is spread by the agency 
of ticks. What particular species of tick is concerned in the 
transmission of redwater in Great Britain and other parts of 
Europe has, however, not yet been conclusively proved by 
experiment, though there is reason to believe that it is the 
Ixodes reduvius. This is almost the only qjoint in connection 
with British redwater about which there remains any obscurity, 
and it is to be hoped that it will soon be cleared up. It is one 
of some importance, for the common British cattle-tick (unlike 
the species concerned in transmitting redwater in America, 
Africa, and Australia) is one of which the young may attach 
themselves in succession to three individual cattle before 
reaching maturity ; and it is therefore uncertain whether the 
piroplasms are passed through the eggs, or are obtained by the 
young ticks while sucking the blood of an infected ox, and 
