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Elementary Biology. 



just beneath the vertebral column, close to the aorta, This 

 system has under its control more especially the intestine 

 and blood-vessels in relation thereto. 



Histologically it will be necessary to glance at the dis- 

 tribution of the three elements of the nervous system the 



FIG. 169. TRANSVERSE SECTION OF THE SPINAL CORD. (Quain.) 



* 



a, b, c, multipolar nerve-cells in the anterior horn of grey matter ; </, pos- 

 terior horn of grey matter ; e, anterior fissure ; _/, central canal ', g, 

 posterior commissure of grey matter ; h, exit of the posterior horn of 

 grey matter ; /, anterior commissure ; k, canal in grey matter ; /, /. 

 nerve-fibres. 



nerve-fibres, nerve-cells, and connective tissue ; and in 



order to do so it will be sufficient to examine a section of the 



cerebrum, a section of the spinal cord and of a spinal nerve. 



Nerve-tissue with a preponderance of nerve- cells has, 



