A New Disease of Cattle. 
235 
parasites. Cases of disease of this kind have been described 
as occurring in most of the common domesticated mammals, 
and occasionally in man himself, but by far the commonest 
subject of coccidiosis is the rabbit. In the rabbit the disease 
very frequently affects the liver, and there produces appearances 
that have often been mistaken for tuberculosis. It also affects 
the intestines of the rabbit, either alone, or in common with 
the liver. Coccidiosis is also a disease of the domesticated 
fowl, but during the last fifteen years only one outbreak of 
coccidiosis among fowls has been detected in the Research 
Laboratory at the College. On the other hand, every year 
in early summer numerous cases of coccidiosis among young 
pheasants come under observation ; indeed, there can be no 
doubt that this is the great plague of young pheasants reared 
under artificial conditions. The deaths usually begin when 
the young birds are a few weeks old, and within a very short 
period the mortality may reach 50 to 80 per cent, of all the 
young birds on the ground. 
The diagnosis after death, or even during life, by examina- 
tion of the faeces is a very easy matter, as the intestines and 
faeces contain great numbers of the so-called coccidia. The 
excrement of these birds infects the ground on which they are 
kept, and it will be readily understood how, in favourable 
circumstances, the disease spreads with alarming rapidity. 
It is, of course, a very well-known fact that it is extremely 
dangerous to use the same ground on two successive seasons 
for pheasant rearing ; but, unfortunately, serious outbreaks of 
coccidiosis may occur among pheasants on fresh ground. 
Probably in these cases the disease is introduced by some of 
the hens used for hatching, for, judging from what is known 
with regard to the similar disease in rabbits, it is not unlikely 
that adult fowls are sometimes the subject of coccidiosis 
although their general health is not seriously affected. 
Reference has been made to this subject here because it 
has more than once happened that when an owner who has 
sent dead pheasants for examination has been informed that 
the cause of death was psorospermosis, he has written, asking 
to be informed in plain English what was the name of the 
disease. Unfortunately, the answer to this has to be that there 
is no plain English or other common term for the disease in 
question. 
A New Disease of Cattle ( Johne's Disease). 
Perhaps the most important fact to be recorded in this 
Report is that, during the past year, cases of a bovine disease 
hitherto not identified in this country have been met with. 
The only justification for calling the disease a new one is that 
