THE ALIMENTARY CANAL AS A SOURCE OF CONTAGION 7 



are well known. On the east of Scotland, however, from the extreme 

 north down to the Lothians, the disease is so rare that some of those 

 engaged in sheep farming hardly know what it is. 



Symptomatology. — The symptoms can be divided into three distinct 

 stages. In the first, the animal, as in so many of these contagious 

 diseases of the sheep, is noticed to be somewhat dull. It may separate 

 from the rest of the flock, stand apart in a listless fashion with drooping 

 head, and be off its feed. It assumes subsequently a reeling gait as if 

 intoxicated, and will lean against a dyke or fence for support. A dazed 

 expression is often noticed in this stage as if the animal were in the 

 initial stage of a fever. 



These symptoms may last for a period of from two to three days, 

 when it falls over quite unable to support itself or to regain, even 

 temporarily, the upright position. The limbs are now spasmodically 

 convulsed at intervals of perhaps a minute to a couple of minutes. The 

 movements are mostly of a galloping character, and so incessant that 

 the turf becomes worn in the area of their excursion. During the 

 intervals, quivering or trembling movements are perceptible, hence the 

 name " Trembling Disease " sometimes applied to it in the Western 

 Highlands. The neck is drawn back as a rule, but the muscles of 

 the neck are not intermittently contracted as in the case of the 

 limbs. The temperature in this, the second stage, may go up to 

 105° to 108° F., and the pulse-rate and respirations are increased in 

 number. The muscles of the jaws and those concerned in swallowing 

 are not usually involved, nor is there any squint, and the intelligence of 

 the animal appears to be little if at all impaired. It will nibble grass, 

 and it swallows milk with avidity and without impediment. 



There are cases, however, which assume quite a tetanic character. In 

 these the muscles are in a state of rigid spasm, while, it is said, although 

 I have never seen an instance of this in the natural disease, the muscles 

 of mastication are in a like rigid condition, and in most respects the 

 phenomena resemble those of idiopathic tetanus. Shepherds in Louping- 

 ill districts will tell you of the occurrence of what they term " lockjaw " 

 among their sheep during the spring months, and from the examination 

 of the carcases of those dying with such symptoms, and for other 

 reasons, I have come to the conclusion that this disease is simply a 

 severe variety of Louping-ill. 



(7) 



