4 Dr. F. W. Mott. Microscopic Changes in the [Feb. 21, 



acute syphilitic meningitis in many ways, except that I can discover only 

 occasional evidence of an obliterative arteritis. ( Vide figs. 1 and 2, Plate 2 

 and Photomicrograph 12.) 



Some of the larger roots seen in the section (vide Photomicrograph 7) are 

 very markedly affected by the inflammatory process. These are judged to be 

 posterior roots, because a posterior spinal ganglion cell can be seen here and 

 there in them ; moreover, they occupy among the roots a posterior position. 

 The capsules of the ganglion cells that are seen are crowded with lympho- 

 cytes presenting an appearance like that observed in Sleeping Sickness. 

 Some of these roots in transection under a high power show the nerve fibres 

 to have been destroyed and their place occupied by proliferated branching 

 neurilemmal connective tissue cells lying in the centre of an oval or circular 

 space bounded by highly vascular thickened, and swollen and amorphous 

 endoneurion. In the centre of most of these cells is a highly refractive 

 round or oval space. (Vide fig. 6, Plate 1.) 



Throughout the spinal cord, but especially at the lumbo-sacral and cervical 

 enlargements, there is a marked thickening of the subpial network of the 

 glia tissue which extends into the white substance along the main septa and 

 branches. ( Vide Plate 2, fig. 2.) 



At the periphery the proliferated glia tissue consists mainly of a dense 

 reticulum of fibrils, but in the substance of the white matter great numbers 

 of large branching neuroglia cells are seen sending their processes in all 

 directions. On careful examination of the longitudinal and transverse 

 sections (vide Photomicrographs 5 and 6), these proliferated neuroglia cells, 

 which are often spoken of as mesoglia cells, can be seen to send their 

 processes to end like a foot upon the wall of a small vessel. This over- 

 growth of glia tissue is seen throughout the white matter of the spinal cord 

 whatever region is examined, but more especially in the lumbar and cervical 

 enlargements, especially the former. It is more obvious in the posterior 

 columns than elsewhere, especially along the median fissure and in the root 

 zone. It does not wholly correspond to system tracts of fibres which have 

 undergone degeneration, but appears (except in the root zone of the posterior 

 column) to be a chronic formative proliferation of the glia tissue caused by 

 an irritant entering the lymphatics and subarachnoid space. The posterior 

 column is much more affected than the rest of the white matter. 



In the lumbo-sacral region there are three definite zones of degeneration 

 in the posterior column, no doubt corresponding to the destroyed roots. 

 ( Vide Photomicrograph 8.) The lymphocyte infiltration is observed around 

 the small vessels and numerous lymphocytes are scattered about in the septa 

 of the white matter. In the roots a well-marked perivascular infiltration 



