THE HISTOLOGY OF DISSEMINATED SCLEROSIS. 



619 



asserted that the areas assumed certain well-defined forms. This apparent depend- 

 ence upon the vessel regions was seen specially clearly in small wedge-like sclerosis 

 situated at the periphery of the spinal cord, in which there was always found a con- 

 densed or even obliterated vessel radiating from the pia. When the area in the 

 white matter was separated from the periphery by a zone of normal fibres it was 

 usually round or oval. These basal forms were in agreement with Kadyi's experi- 

 mental observations on the arterial distribution in the cord, to which we have 

 already alluded. The lateral vessel passed transversely into the cord substance and 

 its first branches were given off transversely, but the transitional vessels ran upwards 

 and downwards in the long axis of the cord. The accompanying figures clearly show 

 that the area of distribution of the transverse branches is wedge-shaped and that of 

 the perpendicular branches is an elongated oval. Such vessels were looked upon by 



Kadyi and Mager as end-arteries, but there is no doubt that there is a considerable 

 amount of overlapping, and that, in consequence of this, the areas supplied by them 

 are not sharply defined. The blood-supply, likewise, of the groups of ganglion cells 

 is not from one individual branch of the commissural vessels, but from several. 

 The sulco-commissural arteries form in the substance of the anterior horn a rich and 

 intimate network which holds the cell groups enweaved in its meshes. 



In the course of this study several small areas have been followed up, serially, 

 throughout their whole extent, and I have come to the conviction that the changes 

 appear within, but do not coincide with, the area of distribution of the arteries, and 

 that it must be extremely difficult to determine the territory of an artery. In 

 literature numerous statements are made to the effect that the position and the 

 definition of the areas corresponded completely to the distribution of individual 

 vessels, but neither in the white nor the grey matter could this be definitely traced. 



In the cord (PI. LXII) the prevailing form of the area at the periphery was 

 wedge-shaped to a certain degree, but in the smaller isolated areas, in which one, or 

 at most two, small lateral vessels were present, the definition was irregular and the 

 shape was ampulla-like, with the neck of the ampulla (fig. 254) at the periphery of 



