CHRONIC SI'IXAL INFLAMMATION. 363 



rigidity of masses of tlio muscular sj'stcm, there is less dis- 

 position to lie down, or when down, a greater difficulty to 

 rise ; these conditions gradually but steadily passing into more 

 or less well-marked deficiency of muscular power and par- 

 alysis, earliest and most marked as paraplegia. Complete 

 paralysis of the posterior extremities is often well enough ob- 

 served in its gradual progress and development, from difficulty 

 to turn rapidly or in a limited space ; disposition to stagger 

 against doorways in passing through them ; inability to move 

 backwards in or out of yoke ; trailing of the limbs, and 

 knuckling over on the fetlocks, or bruising of the one from 

 blows with the opposite foot ; to complete inability to use the 

 limbs either as organs of support or locomotion. 



Chronic inflammatory action of the structures contained m 

 the spinal canal does not, however, in all cases pass through 

 the same phases of disturbed activities ; in some seemingly the 

 diseased condition has existed for some time ere symptoms 

 indicative of spinal changes are obvious, or at least obvious 

 enough to direct our attention to the seat of the lesion. In- 

 stead of first exhibiting spastic contractions or exaltation of 

 special function, we may at once find decided failure of muscu- 

 lar power. Such cases are probably those in which the pure 

 nervous structure of the cord is more largely invaded than 

 the membranes. The extent of the paralysis, the first and 

 probably the only attractive feature of this condition, varies 

 with the exact seat of the spinal lesion ; while from its appear- 

 ance until completely established, the interval is not usually 

 great, exhibition of impairment of motor-power being rapidly 

 succeeded by complete paraplegia. 



Diagnosis. — There are many cases in the horse in which, as 

 in other animals, the difficulties of distinguishing between 

 diseases of the brain and spinal cord are great, seeing that 

 both conditions may be followed by a somewhat similar train 

 of symptoms. In arriving at a correct diagnosis, we are 

 assisted by many considerations, and by a careful observation 

 of collateral phenomena. We must give attention to discover if 

 previous indications of pure cerebral disturbance have ever been 

 observed, or if the animal is subject to megrims or epileps}^ 

 An endeavour may be made to determine if alteration in the 

 position of the head as to elevation, or disturbance of it rudely 



