246 DISEASES OF THE NERVOUS SYSTEM 



the muscular system of paralyzed animals, especially the extremities, be- 

 comes flabby, soft and atrophied. The temperature is reduced in the par- 

 alyzed portion, the extremities being cold and anaemic. In cases 

 where there is paralysis of the spinal cord caused by compression, and in 

 cases of atrophy due to hemorrhage on the spinal cord, and also in certain 

 luxations or fractures of the vertebrae, we practically see the same symp- 

 toms. Paralysis of the extremities, particularly the posterior, may result 

 from the following conditions: 



a. Paralysis of the spinal cord caused by compression may result 

 from thickening of the membranes and pressure on the spine itself. It 

 may also occur in some diseases of the vertebra?, for instance in exostosis, 

 but both of these conditions are very rare. In such cases the symptoms 

 come on very slowly and gradually increase in intensity. 



d. Apoplexy may occur, due to the presence of some blood escaping 

 on the spine and causing pressure. In these cases the paralysis appears 

 very suddenly, but may gradually disappear after some time. 



c. Luxations of the spinal column only happen in the vertebra of the 

 neck, and cause a peculiar oblique position of the head, as if it were twisted 

 to one side. This is due to displacement of the ligaments. At the 

 same time there is present a series of what might be called " special symp- 

 toms," which are not very pronounced in any of their characters. 



b. Fractures of the spine: These are generally recognized by some 

 change in the position of the region in which they are located (bending 

 inward, flattened depressions, and in rare instances slight distortions of 

 the spinal cord), and also by the extensive sensitiveness to pressure in 

 this location. In certain instances there may be an al^normal mobility of 

 the part. Crepitation, as a rule, is absent. In fractures of the cervical 

 vertebrae, we generally notice an ol^liciue position of the head. If the 

 symptoms just described are absent, when an animal has had a severe fall 

 on the spine, unless paralyzed, or remains without loss of consciousness, 

 it is always doul)tful if there is a fracture of the vertebnp or a hemorrhage 

 within the vertebral canal. In such cases we simply have to await develop- 

 ments, or if paralysis docs not immediately follow the injury, but comes 

 some time afterward, it is due to compression of the spine from a grad- 

 ually increasing hemorrhage, ^^'e must I'emember, however, that a fall, 

 shock, or blow upon the back, or ordinary irritations of the spinal sub- 

 stance may occur, like a concussion of the brain, in which there is not the 

 slightest alteration to be found in the spinal substance or its memliranes. 

 In many cases we may expect a recovery as long as there are no myelitic 

 complications. 



Chronic Inflammation of the Spinal Cord. — This condition follows as 

 a sequence to the acute foi'm or it commences at the onset as a gradual 

 progressive affection. It has been contended that overstimulation of the 



