552 NERVOUS DISEASES. 



proves that none of these diseases is similar to Australian string- 

 halt. 



DURATION OF AN ATTACK.—" The attack is sudden in all 

 forms of the disease. A horse may apparently be in good health 

 one day, and on the next be badly affected, and it not unfrequently 

 happens that the horse remains in the same state in which he was 

 found, for nine, twelve, or eighteen months. In slight cases he 

 may recover in five or six months, but the average duration of the 

 disease is about twelve months. Sometimes a horse may remain 

 affected, but be able to work for years ; recovery, however, usually 

 takes place sooner or later without treatment of any kind. When 

 the disease proves fatal, death usually takes place about the fourth 

 or fifth day from the commencement " (Kendall). 



VARIETIES OF THE DISEASE.— Mr. Kendall considers that 

 this malady has three forms, namely, local, general, and acute 

 general. 



" SYMPTOMS OF THE LOCAL FORM.— This is the most com- 

 mon form of the disease, and is characterised by a peculiar jerking 

 action in one or both hind legs, which may be so slight as to be 

 noticeable only when the animal is suddenly turned round or made 

 to go backwards ; but in more severe cases, both hind legs may be 

 so badly affected that progression can only be accomplished by a 

 succession of bounds and plunges extremely painful to witness. 



"There is no involuntary twitching of the limbs as in chorea 

 (St. Vitus's dance), and it is only during movement or attempted 

 movement that the convulsive action is observed. In cases where 

 both legs are badly affected, when the horse desires to move for- 

 ward, the hind quarters are suddenly elevated, and one hind leg 

 is violently jerked upwards, sometimes so high that the foot strikes 

 the belly and remains so drawn up. The other is then brought up 

 in a similar manner, the former being at the same time suddenly 

 brought to the ground with great force. At other times, both hind 

 legs will be jerked up simultaneously, or in quick succession, and 

 the hocks remain flexed to their utmost extent, until the haunches 

 almost reach to the ground, before the horse has power to bring the 

 feet down. 



" In this form of the disease there is generally a great falling 

 off in condition, the animal having a careworn, tucked-up appear- 

 ance. 



"The appetite is almost invariably good, and the digestive and 

 urinary organs appear to perform their functions properly. The 

 pulse is usually quick, even in cases of long standing. In one case, 



