THE NERVOUS SYSTEM OF MAN. 



47 



until we reach nearly to the sacrum, where the cord 

 splits up at once into nerves, but still in pairs, to form 

 the cauda equina — horsetail (Fig. 30, d). 



Fig. 30. — Spinal cord : a, showing the membrane ; *, the two roots ; c, 

 transverse section showing the two roots ; d, cauda equina. 



Section. — On making a transverse section (Fig. 30, b), 

 it is at once seen that the two kinds of nerve matter are 

 found here also. But here, as in the intercranial basal 

 continuation (but not in the cerebrum and cerebellum), 

 the gray matter is within, and the white matter on the 

 outside inclosing it. We see also that the gray matter 

 has a peculiar form, found also in the medulla — viz., 

 that of a semicircle on each side and a connecting band 

 between (Fig. 30, b). As this is only a section view, it 

 is evident that the gray matter on each side is in the 

 form of a plate scrolled outward and connected by a flat 

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