CH. XLII.] 



ASCENDING DEGENERATION. 



6l S 



from below up, and can be traced into the bulb. It consists of 

 fine fibres. The figure represents a microscopic section prepared 

 from a piece of cord some distance above the injury, so that the 

 degenerated fibres which begin in the column of Burdach have 

 passed into the column of Goll. 



(ii.) Dorsal or direct cerebellar tract. This tract is situated on 

 the outer part of the cord between the crossed pyramidal tract 

 and the margin. It is found in the cervical, thoracic, and upper 

 lumbar regions of the cord, and increases in size from below 

 upwards. It degenerates on injury or section of the cord itself, 

 but not on section of the posterior nerve-roots. As its name 

 implies, it passes up into the cerebellum. Its fibres are large, 



Fig. 



Vent' 



i. Ascending tracts of degeneration. The diagram also indicates the position of 

 rite's column (C.C.) and the intermedio-lateral tract (I.T.) in the lateral horn. 



and originate from the cells of Clarke's column of the same side 

 of the cord. 



(iii.) Ventral cerebellar tract, called also the antero-lattral 

 ascending tract, or tract of Gowers. This tract is situated at the 

 margin of the cord outside the corresponding descending tract. Its 

 fibres are of various sizes, and they also originate from the cells 

 of Clarke's column (Schafer). They terminate above principally 

 in the cerebellum, but partly in the corpora quadrigemina. 



(iv.) Tract of Lissaiier, or posterior marginal zone. A small 

 tract of ascending fibres (4 in fig. 452) situated at the outer side 

 of the tip of the posterior coniu. It is made up of fibres of the 

 posterior nerve-roots ; they subsequently pass into the posterior 

 column. 



Complete transverse section of the spinal cord leads to : 



i . Loss of motion of the parts supplied by the nerves below 

 the section on both sides of the body. The paralysis is not 



