THE NERVOUS SYSTEM. 



401 



side in a male and female body, in the ' Ycrh. d. Wiirzb. phys. 

 med./ Gesellsch. 1850, Heft II, and the transverse sectional 

 areas deduced from these observations are given in my 'Micro- 

 scopical Anatomy/ § 116. The roots are furnished with a 

 delicate neurilemma, derived from the pia mater, and present- 

 ing a similar structure, which forms both an external sheath 

 0002'" in diameter, as well as internal septa to the individual 

 fasciculi. The contiguous roots frequently anastomose, and 

 this is much more usually the case with the sensitive roots; 

 in the cervical nerves in Man in particular, it is found to 

 take place constantly in one or other of the nerves.] 



§ 120. 



The structure of the 

 spinal ganglia, in the 

 Mammalia, is a difficult 

 subject of investigation, 

 but I think the following 

 may be stated with cer- 

 tainty respecting them. 

 The sensitive roots, so far 

 as I have hitherto been 

 able to make out, enter 

 into no connection with 

 the nerve-cells in the 

 ganglion, but forming 

 one, or, in the larger 

 ganglia, several, or even 

 numerous fasciculi, which 



Fig. 154. A lumbar ganglion 

 of a young Dog, treated with 

 soda, and magnified 45 diam.: S, 

 sensitive roots ; M, motor roots ; 

 R.a, anterior branch of the spinal 

 nerve ; Ji.p, posterior branch ; in 

 both their composition from both 

 roots is manifest; G, ganglion, 

 with the cells and ganglion-fibres, 

 which assist in the strengthening 

 of the sensitive roots traversing 

 the ganglion. 



Fig. 154. 



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Am 



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