476 Hemisection of the Spinal Cord in the Cat. [Mar. 21, 



(c.) Sensation. This is always interfered with on the side of the 

 lesion. Painful sensations, such as those produced by the prick of a 

 pin, or by touching the foot with a piece of wire which is slightly 

 heated, appear to be felt on both sides, and this was well seen in the 

 monkeys which were used as control experiments ; but the evidence 

 seems to show that these painful sensations are more quickly felt on 

 the non-paralyzed than on the paralyzed side, and also that the 

 animal does not localize the painful spot on the injured side with 

 anything like the precision that it does on the unaffected side. 



Tactile sensations, such as those produced by the presence of a 

 small clip applied to the skin, are only felt on the non -paralyzed side ; 

 the animals were frequently seen to remove the clip from this side, 

 but unless their tails touched it when placed 011 the paralysed limb, 

 or their attention was directed to its presence in some such way, no 

 notice whatever was taken of it. 



The same result was seen with the cold-water test. When water 

 was brought in contact with the feet, the unaffected limb was at once 

 withdrawn and the water licked off it, while on the opposite side the 

 foot was allowed to stand in a pool of water without any notice being 

 taken of it. 



Microscopic Examination of the Spinal Cords. 



The portions of the cords containing the lesion were carefully 

 examined for the purpose of ascertaining their exact extent, and a full 

 description is given in the paper. 



The following is a short description of the degenerations found in 

 the cord. 



(1.) Descending Degenerations. These degenerations were confined 

 almost entirely to the side that was cut, and they occupied the direct 

 and crossed pyramidal tracts; a few scattered degenerated fibres 

 were seen in the antero-lateral tracts of both sides ; this was especially 

 marked in the cases where a small part of the opposite half of the 

 cord had become accidentally injured. 



(2.) Ascending Degenerations. These degenerations were not 

 entirely confined to the side of the lesion. 



The tracts that contained most of the degenerated fibres were the 

 column of Goll, the direct cerebellar tract and the antero-lateral tract. 

 Some degenerated fibres were usually found in the opposite column 

 of Goll, and also in the antero-lateral tract of the uninjured side. 



