422 DISEASES OF THE HORSE’S FOOT 
brought about by pyemia. This is indicated by the swollen 
and cedematous nature of the lymphatics of the limb. Plainly 
enough they indicate the road by which the poison has 
travelled. It isin this way: Pus and putrefactive organisms 
have gained entrance to the lymphatics of the original 
diseased limb. From these they have rapidly gained the 
blood-stream and set up infection elsewhere. In this par- 
ticular instance it is demonstrated by the laminitis and 
lymphangitis of the previously sound limb. With the 
poison thus circulating in the blood-stream, we often also 
get spots of infection commenced in one or other of the 
more vital organs—notably the lungs or the kidneys. The 
end of our case is then either a gangrenous pneumonia or 
complications induced by a condition of widespread pyzmia. 
With the animal in slings there are one or two other 
symptoms that call for attention. In many cases, especially 
with animals of a lymphatic and indolent nature, the use 
made of them is inordinate. The patient rests so continually 
in them that alarming swellings commence to make their 
appearance about the rectum, or in the case of a mare 
about the vulva. The animal must then be let down at 
regular intervals and again raised when rest is obtained. 
A more alarming symptom still is when the animal, 
instead of resting in the slings by his buttocks, casts his 
weight bodily into the belly-rest and hangs with a heavy 
head into the head-stall. This indicates complete exhaus- 
tion and a wish for death. Matters should therefore be 
explained to the owner, and his consent obtained for 
immediate destruction. 
Pathology—The pathological changes occurring in sup- 
purative arthritis we shall pass over briefly. It is almost 
sufficient, in fact, to say that the whole of the joint becomes 
completely disorganized. 
The synovial membrane becomes so tremendously 
thickened and injected as to be scarcely recognisable as 
such, the thickening in the later stages being due to large 
growths of granulation tissue which entirely alter the 
appearance of the membrane as we know it normally. 
