1907.] on Certain Seasonal Diseases of the Sheep. 545 



herds 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. 



The animal may succumb in this second or convulsive stage, 

 apparently from acute toxic poisoning. It passes into a semi- 

 comatose state, the temperature sinks, and the convulsive spasms 

 become weaker and weaker, preliminary to the fatal termination. 



Should the disease not prove fatal within a matter of a week or 

 less, then there is every likelihood of its passing into the third stage 

 characterised by the following phenomena : The convulsive spasms 

 of the limbs, so notable in the second stage, now give place to a 

 condition of more or less complete motor paralysis ; the limbs are 

 outstretched and limp, while, if the sheep be held up l:>y the fleece, 

 they hang down relaxed and listless, and the animal is quite unable 

 to use them for purposes of support. When the feet touch the ground 

 the fetlocks are knuckled under in a perfectly helpless manner. 



Painful sensation, so far as one can judge, does not seem to be 

 affected to any apprecial)le extent even in this stage, but the reflexes 

 from the limbs appear to be blunted, and in certain cases annulled. 



The whole appearance of the animal closely resembles that of a 

 person suffering from post-diphtheritic paralysis, the nature of the 

 paralysis being essentially motor, and affecting the limbs by pre- 

 ference, although it seems to differ from the diphtheritic form in the 

 fact of the palatal muscles being spared. During the course of the 

 disease the animal is able to swallow liquid nourishment without im- 

 pediment. The intelligence in this third or paretic stage often 

 remains uninfluenced. The animal recognises objects about it, 

 and will bleat when a companion sheep is removed into a neigh- 

 bouring pen. It will eat fodder if offered to it, but is quite helpless 

 to seek for such of its own accord, and, as a consequence, in many in- 

 stances, seems to die from starvation as much as from any other cause. 



In this highly paretic state it may live for weeks, recovery seldom, 

 if ever, taking place, even though the animal may have been fed 

 artificially. Some subjects of the disease are said to make a partial 

 recovery, probably only one limb remaining permanently crippled. I 

 have always been somewhat doubtful, however, of the diagnosis in 

 such cases ; the symptoms look to me more like the effects of spinal 

 abscess, which is very common, at least among lambs, during the 

 spring months. 



Morbid Anatomy. — On examining the carcase in this disease one 

 of the most notable features is the absence of lesion which might 

 serve to localise the peccant agent in any particular organ. Gas 

 begins to develop in the abdomen very soon after death, and within 

 a few hours, in certain instances, the wall of the abdomen may 

 assume a greenish tint. 



Vol. XVIII. (No. 101) 2 n 



