THE NERVOUS SYSTEM. 12] 



the peripheral ones, and in the female nearly sufficient, particu- 

 larly when it is considered, moreover, that in the entire enume- 

 ration, the numbers were stated rather in favour of the roots 

 of the nerves (vid. the calculation in 'Mikroskop. Anatom.,' 

 II, 1, § 116). 



It appears, therefore, scarcely to admit of doubt, that the 

 notion of a termination of the peripheral nerves in the cord, 

 has no support in measurements such as those which, following 

 Volkmann, I have adduced; and that the latter, even when all 

 due allowance is made for the uncertainty always incidental to 

 such an inquiry, on the contrary indicate, at all events II 

 probability, that the spinal nerves ascend to the cerebrum. 

 They give no further information, however, and it depends 

 upon other facts, whether such a central origin should be 

 admitted or not, because it is even conceivable, that the 

 peripheral nerves may end in the cord, and that the longi- 

 tudinal fibres in the cord have a wholly different source. 

 Since it is scarcely probable that the tracing of the nerve- 

 fibres through the entire cord will be effected either at present 

 or perhaps at any time, it is necessary to look round for other 

 facts, which may possibly afford conclusive evidence on the 

 subject; and such facts do exist. In the first place, let us 

 consider the course of the roots of the nerves in the cord, such 

 as it has been described above. We found, that after they had 

 all come, more or less, into contact with the grey substance, the 

 greater number of them could be directly traced into connection 

 with the longitudinal fibres of the anterior, lateral, and pos- 

 terior columns. From this fact, together with my measure- 

 ments, the passage of the greater part of the peripheral nerve- 

 fibres into the cerebrum, will appear to many to be proved; 

 but, not to overlook anything, it may further be remarked, that 

 the radical fibres, running longitudinally in the substance of 

 the cord, may terminate in it, or after running in it may 

 again enter the grey substance higher up. The former sup- 

 position is now, it must be confessed, but little probable, 

 because in the first place, no one has yet seen the terminations 

 of nerve-fibres in the white substance ; and in the second, 

 because anything of the sort, for other reasons, would be very 

 surprising, nerve-fibres being nowhere known to commence in 

 the white substance; and with respect to the latter, any re- 



