Symptoms. 683 



if the compression involves the brachial plexus only. The pa- 

 ralysis in most cases develops slowly, the first symptoms be- 

 ing a certain weakness of the hind quarters. This increases 

 with periods of improvement until there is complete sacral 

 paralysis, in which case the hind legs are dragged along. On 

 the other hand, the case may get worse so rapidly that the 

 animal appears to become paralyzed suddenly, but in such 

 cases, the atrophy of the muscles indicates the slow develop- 

 ment of the disease. 



As the paralysis increases, the muscular tone decreases, 

 and there is a rapidly progressive atrophy of the muscular 

 tissue. If the paralysis is due to compression of the cord, the 

 motor nerves remaining uninjured, there is no loss of muscu- 

 lar tone. In many cases there is a decrease in the suscepti- 

 bilitv to electricity. 



The hyperalgesia which, at the commencement, is evidenced 

 by subjective symptoms, for a time increases as the motor 

 disturbances progress. Light contact with the hair or a tap 

 on the skin, etc., may cause symptoms of severe pam, while 

 in other cases animals, which are obviously restless owing to 

 paresthesia, bite their limbs until they are sore. Passive move- 

 ments of the spine or percussion of the spinous processes m 

 some cases cause symptoms of pain, but the position of the 

 pain cannot be localized. In the later stages, the hyperalgesia 

 may be replaced by hyperesthesia or complete anesthesia over 

 limited or large areas. 



At the onset of the disease all reflexes appear to be exag- 

 gerated. In many cases, muscular contractions may be caused 

 by quite slight contact with the skin, scratching with the point 

 of a needle, etc., and these may also involve the opposite side 

 of the body. If the sole of the foot be scratched there is not 

 simply a sudden flexion of the phalanges, but also an active ex- 

 tension of the whole of the opposite limb. Among the tendon 

 reflexes the patellar reflex is most frequently increased, but 

 in a large number of cases, active and very rapid contractions 

 of the particular muscles are caused by percussion of the tendo 

 Achillis, of the extensor tendons in the lower third of the fore 

 arm or in the metacarpal region, the tendon of the tibialis ant- 

 icus, the flexor metatarsi, and the distal tendons of the anco- 

 neus muscles. The priapismus which is sometimes observed 

 affords further evidence of the increased reflex irritability, an 

 erection being easily induced bv rubbing the skin of the abdo- 

 men the prepuce or the urethral bulb. If the finger be intro- 

 duced into the rectum, the sphincter is thrown into repeated 

 contractions and, as in stimulation of the abdominal skm, there 

 is an involuntary and full flow of urine. This symptom must 

 not be attributed to paralysis of the bladder. 



In the later stages, reflexes disappear m those parts m 

 which the motor and sensory nerves have lost their conduc- 

 tivity, while in cases in which there is compression of the cord 



