Symptoms. 709 



ralysis, and the slowly increasing but slight atrophy of the 

 affected muscles, there is in some cases an active rigidity of. 

 the muscles in the portion of the body posterior to the seat of 

 compression of the cord. This rigidity is evidenced by a firmer 

 consistence and an increase in the passive resistance offered by 

 the muscles, and also by extension and even crossing of the par- 

 alyzed limbs. This is especially obvious when the animal is 

 sitting or lying down (fig. 101). In consequence of the rigid- 

 ity of the muscles, which in some instances is pronounced while 

 the paresis is still slight, the gait is spastic, the joints are 

 scarcely flexed, and the feet are dragged along the ground. 

 Dogs walk on the tips of their toes (fig. 97, page 682), slip up 

 on smooth surfaces and fall over if they attempt to jump upon 

 anything. In many cases, on the other hand, the feet are lifted 

 backwards and quickly put down again. 



In numerous cases that have been examined no actual ataxia has been dis- 

 covered either 1)y Dexler or Hutyra & Marek. The very variable symptoms are 

 entirely caused by loss of muscle power or by the muscular cramp. 



In addition to the pain already mentioned, sensation be- 

 hind the seat of compression appears to be decreased or even 

 quite lost, but not rarely, and even when there are pronounced 

 symptoms of paralysis, there may be very slight disturbances 

 of sensation or none at all. The insensitive area is not 

 rarely limited anteriorly by a hyperalgesic zone which corre- 

 sponds with the area supplied by the sensory nerves, the roots 

 of which are subjected to pressure. The pain may be so severe 

 that the animals bite the affected part until they draw blood. 

 If there is tumor-, callus-formation, or luxation, the spine 

 shows a circumscribed swelling, and in many cases of caries 

 there may be a recognizable excrescence. In small animals, 

 there may be evidence of pain if the superior spines be struck 

 or subjected to pressure and even during passive motion. Ex- 

 ceptionally, it is possible to determine pronounced passive 

 mobility of some part of the spine. 



Posterior to the seat of compression, the reflexes are ex- 

 aggerated, but in parts where the compression is somewhat 

 more extensive, there may be a complete absence of reflexes. 

 The frequent erections of the penis which are easily caused by 

 stimulation of the skin of the abdomen, of the prepuce or the 

 penis are the result of the exaggerated reflex irritability. 



Abnormalities of function of the bladder and rectum are 

 frequently observed. In view of the fact that tlie compression 

 is usually situated in the middle of the lumbar portion of the 

 cord, there is, as a rule, retention of urine and feces. In many 

 cases, the animals are unable to pass urine or feces voluntarily. 

 In a greater proportion of cases there is an involuntary dis- 

 charge of urine and feces at long intervals. This discharge 

 can also be induced by external influences, such as pressure on 

 the wall of the abdomen, or the region of the bladder or peri- 

 neum. Urination takes place at very short intervals, sometimes 



