Symptoms. 707 



side the nerve fibers were destroyed, the vessel walls were thickened, and their 

 sheaths were infiltrated with round cells. The nerve cells were more or less de- 

 generated, and, in cases that had been in existence for more than a year, the tissue 

 of the cord was invaded by a fibrous tissue that was poor in cells but which con- 

 tained here and there a few unaltered fibers or groups of nerve cells. In some 

 cases the fibrous tissue contained numerous cavities containing a serous fluid (great- 

 ly dilated lymph spaces). In the other parts of the cord there were degenerations of 

 a secondary nature. Above the seat of tlie compression the posterior columns de- 

 generate as far as the nuclei in the medulla as do also the lateral cerebellar tracts 

 and Gower's tract. The motor tracts and the comma tract of Schultz degenerate 

 in the caudal direction. At the seat of the compression the nerve fibers contained 

 in the nerve trunks originating from the degenerated motor nerve roots may also 

 be in a condition of degeneration. 



Symptoms. A common symptom is tlie evidence of pain 

 wliicli sometimes precedes the other symptoms by long periods. 

 The pain may be either constant, in which case the animal holds 

 the spine rigid and somewhat arched, or it may be intermit- 

 tent and manifest when the animal gets up or lies down, and 

 during movement or jumping, causing the animal to cry out. 

 Owing to the pain, movements are executed with care. In some 

 cases in which the cervical portion of the spine is involved, the 

 animal may be unable to take food from the ground or to 

 graze. 



Motor disturbances may be observed in some cases simul- 

 taneously with the appearance of sjanptoms of pain. In other 

 cases they appear later, but they may be observed without any 

 preliminary symptoms indicative of pain. These disturbances, 

 as a rule, first affect the hind quarters irrespective of the seat of 

 the disease, owing to the fact that the muscles of the hind 

 quarters play a greater part in the execution of body move- 

 ments than those of the fore limbs, and consequently any weak- 

 ness in them is observed sooner. It is only in exceptional cases 

 that the weakness sets in in all four limbs at once, and it scarce- 

 ly ever happens that the fore liml)s are affected more severely, 

 or exclusively so. As a general rule, the loss of power is 

 bilateral, but in some cases this is not so, and the difference 

 may be so pronounced between the two sides that a superficial 

 examination may lead one to think that the paralysis is unilat- 

 eral or involves "a single limb only. In exceptional cases, if for 

 example only one side of the cord is subjected to pressure, there 

 may be a true unilateral paralysis or monoplegia (Brown-Se- 

 quard type). Goldmann records a case in which a pig showed 

 sensory and motor paralysis of one hind leg, owing to an echino- 

 coccus in one of the dorsal vertebras. 



In typical cases, motor disturbances are observed in the 

 larger animals. The animals rise slowly and with caution, cat- 

 tle get up like horses, or remain sitting like dogs for a long 

 time. In some cases, they lower themselves on their hind legs 

 while urinating, in the manner frequently observed in puppies 

 (Hamoir and Stenstrom). In such cases, weakness of the hind 

 quarters is always observable and especially when the animal is 

 turning. Small animals, and especially dogs, are no longer able 

 to jump up or to stand on their hind legs. 



