438 



DISEASES OF THE NERVOUS SYSTEM. 



FIG. 209. 



Chronic transverse myelitis may follow an acute attack, the 

 chief characteristic being a marked increase in the neuroglia- 

 tissue in addition to the changes already noted. Similar 

 changes may also be produced by chronic compression of the 

 cord resulting, for instance, from the growth of a tumor in 

 the meninges (Fig. 209), or the bony deformity produced by 

 Pott's disease. 



Acute anterior poliomyelitis is an acute inflammation of the 

 anterior cornua of the gray matter of the cord accompanied 



by marked systemic disturbances. 

 On account of its greater frequency 

 in childhood, the condition is known 

 clinically as "infantile paralysis," 

 though the disease does occur in the 

 adult, and is recognized as " acute 

 spinal paralysis." Nothing definite 

 is known as to its course, though 

 by many it is regarded as an infec- 

 tious disease, having a selective 

 action on the tissues which are 

 affected. 



Macroscopically, characteristic 

 alterations, which are most marked 

 in the lumbar and cervical enlarge- 

 ments, may be entirely absent at an 

 early stage of the disease, though 

 the changes consecutive to the cessa- 

 tion of the acute inflammatory proc- 

 ess are quite obvious, consisting 

 of sclerosis and atrophy of the 

 anterior gray coruna and the 

 ante ro -lateral white columns. 



Microscopically, at an early stage 

 the bloodvessels of the anterior 

 cornua are dilated and surrounded 

 by migrated leukocytes, and there 

 have also been noted swelling and granular degeneration of 

 the large ganglion-cells. At a later stage, even within a few 

 days of the onset of the disease, the ganglion-cells lose their 



Meningitis and 

 pression 



3 and beginning 

 -myelitis from an 



dural tumor (Bock). 



rom an extra- 



