CEREBRO-SPINAL MENINGITIS 145 



the difference in environment must, to a corresponding 

 extent, affect the results. 



We would here remark that the more or less plugged 

 condition of the central canal may frequently have its 

 origin in this morbid process, and that the occurrence of 

 hydro-myelia and syringo-myelia may, in many cases, have 

 indirectly to be attributed to it. 



Moreover, the similarity of the consistence and sub- 

 stance of the deposits or exudates to be found in the 

 intra-spinal spaces, and especially in the lower termination 

 of the cerebro-spinal cavity in some cases of cerebro-spinal 

 meningitis, and in the central canal in some cases of 

 syringo-myelia, lends suspicion, to say the least of it, to 

 the supposition that they owe their existence to an almost 

 common cause, and are produced by similar conditions 

 eventuating in obstruction of the central canal and rupture 

 of its walls, with consequent invasion, obliteration, and 

 dissipation of the proper or neuroglial substance of the 

 cord. 



