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margin ; and in a suitably prepared specimen the sjoeck will 

 be seen to rest over a well-marked horizontal band of 

 medullated fibres. Thus, the primary pale band may be de- 

 monstrated to owe its whiteness, as appears to have been 

 appreciated by Meinert, to the dense nucleated protoplasm 

 within it, and to be limited internally by those horizontal 

 fibres to which it has frequently been supposed to owe its 

 special character. 



Immediately beneath the primary pale band pyramidal 

 corpuscles may again be found as large as those superficial to 

 it ; but I think not always so. There seem to be always 

 present here nerve- corpuscles of more irregular form, and 

 the size diminishes the further we penetrate towards the 

 white substance I am disposed to think that Meinert is 

 correct in describing another densely nucleated stratum in 

 connection with the second pale band when that is present ; 

 but there is certainly, also, in connection with it, a stratum 

 of horizontal medullated fibres, such as there is in connection 

 with the primary pale band. 



The nerve fibres in the convolutions are of two sets, those 

 which are vertical to the surface, and those which are hori- 

 zontal to it. The vertical fibres, coming up from the interior, 

 as soon as they reach the grey matter split up, as is well 

 understood, into bundles ; and in the intervals between 

 these the nerve corpuscles and free nuclei are found, so that 

 they appear to be packed in vertical rows. In the deeper 

 layers the fibres are broad, the axis cylinders being coated 

 abundantly with medullary sheath; but as they proceed 

 onwards each fibre becomes gradually thinner, and by this 

 means the bundles get narrower. Tracing them onwards 

 through the outer layer of small nerve corpuscles, they are 

 seen to spread out, so as to be uniformly distributed and no 

 longer parallel ; but they continue to make for the surface, 

 and only turn round to become horizontal in the external 

 nucleated protoplasm. The horizontal fibres have been 

 termed arciform fibres by Lockhart Clarke. There is a dense 

 stratum of them medullated, situated immediately beneath 

 the grey matter. As has been already stated, there may be 

 one or two strata of fibres separated from this, corresponding 

 to the inner edges of the pale bands seen with the naked 

 eye ; also scattered medullated fibres are found in the in- 

 tervals between these strata ; and, at least in sections cutting 

 the convolutions longitudinally, others may be seen passing 

 very obliquely from one stratum to another. But more 

 superficially there still continue to be disposed numbers of 

 horizontal fibres, not so easily seen on account of the slight- 



