694 THE FEATURES OF DIFFERENT REGIONS. [BOOK in. 



the anterior (Fig. 119) and the posterior (Fig. 120) columns 

 agree to a certain extent with the grey matter in shewing a 

 decided increase in both the lumbar and the cervical swellings. 

 We may, provisionally at least, infer from this that, while con- 

 siderable portions of both the anterior and the posterior col- 

 umns are like the adjoining grey matter in some way or other 

 concerned in the exit and entrance of efferent and afferent 

 fibres, the larger portion of the lateral column is concerned 

 in the transmission of impulses to and fro, between the local 

 mechanisms below, immediately connected with the several 



V IV III II I V IV III II I XII XI X IX VIII VII VI V IV III II I Vlil VII VI V IV III U I 



FIG. 118. DIAGRAM SHEWING THE VARIATIONS IN THE SECTIONAL AREA OF 

 THE LATERAL COLUMNS OF THE SPINAL CORD, ALONG ITS LENGTH. 



in n i v iv ui u i xu xi x ix vui vu vi v iv m u I vui vn vi v iv in n i 



FIG. 119. DIAGRAM SHEWING THE VARIATIONS IN THE SECTIONAL AREA OP 

 THE ANTERIOR COLUMNS OF THE SPINAL CORD, ALONG ITS LENGTH. 



V IV III II I V IV III II I XII XI X IX VIII VII VI V IV III II I VIII VII VI V IV UI II I 



FIG. 120. DIAGRAM SHEWING THE VARIATIONS IN THE SECTIONAL AREA OF 

 THE POSTERIOR COLUMNS OF THE SPINAL CORD, ALONG ITS LENGTH. 



spinal nerves, and the brain above. This conclusion seems 

 incidentally confirmed, (though these diagrams must not be 

 strained to carry detailed inferences,) by the sudden increase 

 of the lateral column above the lumbar swelling, as if the large 

 mass of nervous mechanism for the lower limbs concentrated 

 in this region demanded a sudden increase in the number of 

 fibres connecting it with the brain above. 



This more or less continuous increase of the lateral column 

 partly explains the change of form in the general outline of 



