422 DISEASES OF THE HORSE'S FOOT 



brought about by pyemia. This is indicated by the swollen 

 and oedematous nature of the lymphatics of the limb. Plainly 

 enough they indicate the road by which the poison has 

 travelled. It is in 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 pyfemia. 



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. 



