51 



deeper neurones of the nucleus. In Pi£.'^ there is shown an 

 incominf^ ner-ve-fibre, g.c.f., breaking up into its arborization 

 near one of these neurones. The arborization is of the broad- 

 ly digitate variety, spreading the disturbance over some slight 

 area. The scattered distribution of the neurones at this point 

 is doubtless a correlative of this fact. 



Finally, the molecular layer which caps the whole nucleus 

 contains many fibres of quite minute size. This level, with 

 its small branching neurones, and the dendrites froni deeper 

 70nes, may serve to distribute impressions superficially. 



Turning to the spinal V tract, this is a series of bundles 

 of fibres which run posteriorly to the spinal cord. The bun- 

 dles are scattered through the deeper part of the general cuta- 

 neous nucleus; refer to Fig. 48, sp.V. General cutaneous fibres 

 may enter the nucleus directly fron^ the nerve of the same side, 

 or through the mediuir of the arcuate bundles from the opposite 

 side. They may terminate at once in the nucleus, as described 

 above; or they may turn into the spinal V tract for termination 

 farther posteriorly. Some of those present in the tract are 

 doubtless branches of fibres which have termirated in part in 

 the nucleus. The spinal V tract, then, is a means for carry- 

 ing great numbers of sensory nerve-fibres from cranial nerves 

 to the dorsal cornu of the spin^sl cord, giving them a second 

 and far wider hold. 



The manifold central terminations of the general cutane- 

 ous system must have a significance, if we can but interpret 



