'322 T ^ E BIOCOSMOS PARTICULARIZED. 



must be a going and a returning. The Spinal 

 Cord is cleft lengthwise by a fissure which 

 quite halves it, the two parts being united by 

 a little neck of gray matter, while the white 

 matter lies on the outside of the cord. The 

 motor fibre from the nerve is what makes the 

 muscles contract. 



The two lines of the Ganglionic or Sympa- 

 thetic System have to do with the viscera, the 

 inward-turning organs. They branch from 

 the spinal nerves near the spinal column and 

 form a row of ganglia on each side of the 

 body, and the two rows unite in one ganglion 

 at the pelvis. They resemble two knotted 

 ropes suspended on each side of the spine and 

 tied together below an inner and outer spinal 

 cord controlling inner and outer organs of 

 Assimilation. Hence there is a sort of dupli- 

 cated Spinal Cord, the outer being protected 

 by its bony walls. These nerves are respect- 

 ively called the cerebro-spinal and sympathe- 

 tic Systems. The main ganglionic line divides 

 into subordinate groups of ganglia forming 

 an intricate network known as plexuses (for 

 instance, the solar). Crawfish and insects 

 have chiefly the ganglionic System and thus 

 indicate a starting-point of nerve evolution. 



The work of the Nerves proper in the Or- 

 ganism has been often compared to that of 

 the Telegraphic System with its thousands 



