LECTURE XIII. 



APRIL 3, 1858. 

 SPINAL COED AND BRAIN. 



The spinal cord White and grey matter Central canal Groups of ganglion-cells 



White columns and commissures. 



The medulla oblongata and the brain Its granular and bacillar layer. 

 The spinal cord of the petromyzon and its non-medullated fibres. 

 The intermediate substance (interstitial tissue) Ependyma ventriculorum .Neuro- 



glia Corpora amylacea. 



THE last time, gentlemen, I laid before you the results 

 of the most recent observations concerning the nature and 

 distribution of the ganglion-cells in the great nervous 

 centres ; allow me now to dwell a moment upon that 

 organ which serves as a type in the development of the 

 vertebratae, and is at the same time the one whose struc- 

 ture we can best take in at one view, namely, the spinal 

 cord. 



The spinal cord presents, as is well known, and can 

 with ease be seen by the naked eye in any transverse 

 section, in different parts of its course, a different amount 

 of white matter, though nearly everywhere the white 

 matter predominates over the grey. This appears in 

 transverse sections in the form of the well-known horns, 

 which are distinctly marked off from the pure white of 

 the rest of the mass by their sometimes pale grey, some- 



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