476 NERVOUS SYSTEM. 



Symptoms. Clinically the disease occurs in two forms, one termed 

 the convulsive form, the other the pruriginous form. In the convulsive 

 form the patients rapidly lose appetite, soon appear unable to stand, fall 

 on their sides, and exhibit spasmodic contractions of certain groups of 

 muscles. After a time the clonic contractions may give place to per- 

 sistent rigidity. The patients are carried off rapidly in a week or two 

 without other important symptoms. This disease appears to exhibit 

 certain analogies with louping-ill, but these do not seem to be recog- 

 nised in France, where it chiefly occurs. 



In the pruriginous form the beginning of the attack is obscure, and 

 only the shepherd is able to note anything unusual. The animals move 

 in a jerky way, the hind limbs being lifted at times after the manner of 

 a horse suffering from stringhalt. They are excitable, exhibit trembling 

 movements when touched, with convulsive movements of the head, and 

 present an anxious and vacant appearance. The development of these 

 symptoms, which constitute what may be termed the first phase of the 

 disease, is sometimes prolonged, and in winter may last from one to two 

 months. In summer it rarely lasts longer than a week or two. 



At this stage a special pathognomonic symptom develops, viz., intense 

 and permanent pruritus of the hind quarters, which causes the animals 

 to rub the croup against any projecting objects, walls, mangers, etc. 

 They thrust themselves backward against the object, and rub with 

 such violence that the wool is torn away and the skin itself often 

 excoriated, although the irritability appears to be in no wise dimin- 

 ished thereby. In the fold the animals sometimes rub against one 

 another, making their sides raw, and bite themselves on the croup, 

 the quarters, and the tail. 



When the affected parts are touched with the hand, peculiar move- 

 ments of the head and the li]3S are immediately excited, similar in 

 character to those caused by mange. Up to this time the animals 

 continue to feed, but they progressively lose condition, become weak 

 in the hind quarters, and fail to keep up with the other animals in 

 the flock. Their gait becomes hesitating; they move with a trotting 

 step and appear semi-ataxic. 



All these symptoms develop without fever, but become aggravated 

 from day to day, until they end in paraplegia and death. This second 

 phase lasts for a period of from two to four months in winter. 



Lesions. No lesions can be detected on a simple examination of the 

 dead bodies. Gilbert has mentioned a change in the blood ; Trasbot, 

 chronic inflammation of the pia mater and of the lumbo-sacral portion of 

 the spinal cord. German writers have described sclerotic changes in the 

 posterior portions of the cord. Moussu has carried out a large number 

 of examinations, but has never found these lesions, either on anatomical 



