750 PARALYSIS OF THE HIND EXTREMITIES. 



of vertebrae, disease of the inter-vertebral discs, or still more frequently 

 muscular disease, which may be of a rheumatic character, due to 

 chill, or of purely mechanical origin. In the horse the latter is more 

 frequent, because in it violent, intrinsic, or extrinsic, over-extension 

 of muscle produced during heavy and unwonted exertion is common. 

 When animals are continuously overworked, permanent interference 

 with muscular function in time results, causing the mechanical efficiency 

 of the muscle to become impaired. The resulting disturbance has 

 been referred to disease of the fasciae, but the truth of this statement 

 has never been satisfactorily established. In this form muscular 

 atrophy is well marked. 



V oiler describes a form of paraplegia which suddenly developed in a 

 mare after parturition, simultaneously with deformity of the spinal column 

 between the 14th and 15th dorsal vertebra?. The animal could stand, 

 but could only walk with difficulty ; it made rolling movements with the 

 hind- quarters. At first, movement was greatly interfered with, but after- 

 wards improved, though the spinal deformity continued. Johow saw a 

 fifteen- year- old horse which had suffered from weakness of the hind-quarters 

 for a period of six months. The difficulty was greatest in the morning 

 on getting up and making the first few steps. One day complete paraplegia 

 suddenly set in. The body of the first lumbar vertebra was found, on 

 post-mortem, to be one-third thicker than that of the others. The 

 thickening encroached on the vertebral canal and pressed on the spinal 

 cord, which had correspondingly diminished in thickness. 



Harms found the connection between the anterior ends of the glutei 

 maximi and the longissimus dorsi torn away on both sides in a four- year- 

 old horse. When resting, nothing remarkable could be seen, but during 

 movement the hind-quarters rolled from side to side. A large cavity 

 could be seen on either side of the spinal column, at the point where the 

 large gluteus arises from the longissimus dorsi. In front of the ilium an 

 elevation was noticeable. After movement, the anterior end of the large 

 gluteus returned to its normal position, as could easily be seen. No 

 improvement occurred. 



Prognosis in complete paraplegia is unfavourable, and only those 

 cases due to concussion of the cord have any chance of recovery. 

 In large animals the prognosis is much less favourable than in small 

 ones, the former always dying at an early stage from decubital necrosis 

 and horses even sooner than catttle. 



In incomplete paraplegia, the prognosis naturally depends princi- 

 pally on the nature of the causative process. Recent and sudden 

 cases, especially those resulting from accident, offer more hope of 

 recovery than the more chronic, which are generally due to some 

 incurable disease. The condition usually becomes gradually 

 worse, though at times it seems to remain nearly stationary, and 

 allows animals to be used for considerable periods at a walking pace. 



Treatment. In paralysis, the animal must have a suitable soft 



