212 
THOMPSON YATES LABORATORIES REPORT 
The experiments were chiefly carried out in the lumbo-sacral region. Of two observations 
made on the condition of the cells in the spinal cord after section of the afferent roots in the region 
of cervical enlargement, one gave a negative result, and the other showed a distinctly less amount 
of change than that noted in the seven cases where the similar operation had been performed in 
the lumbo-sacral region. 
I have made two further experiments in the cervical region. 
Exp. I. Cat. Killed OJi the \\th da^^. %th cervical^ 1st afid llnd dorsal posterior roots divided on one side. 
Vlllth segment. Series of 95 sections cut — ganglion cells of ventral horn nearly normal ; only six 
showed distinct alteration. 
1st dorsal segment. Series of 140 sections cut — 20 altered cells found, which were situated as 
follows : — 
Ilnd dorsal segment. No altered cells found. No altered cells on opposite side. 
Exp. 2. Cat. Killed on \\th day. Vth, FIth, VII th, Vlllth cervical and 1st dorsal posterior roots 
divided on one side, and the Vlllth cervical on both sides. 
Vth, Vlth, Vllth segments contained no altered cells. 
Vlllth segment. Series of 140 sections cut. 20 altered cells found, situated as follows : — 
1st Dorsal Segment. A few altered cells found near the central canal. 
These two observations confirm the results recorded in my previous communication, and 
show that while some alteration in the cells of the anterior horn does result from a lesion of the 
afferent roots, the change is considerably less than that occurring after a similar procedure in the 
lumbo-sacral region. It is to be noted that such change as occurs is limited to the Vlllth cervical 
and 1st dorsal segments. The significance of this localization was previously discussed and is held 
to be connected with the fact that the anterior roots of these segments are dist.nbuted to the 
muscles of the hand, the movements of which as shown by Sherrington and Mott are practically 
abolished after severance of the afferent roots. In the lumbo-sacral region the altered cells were 
found to be chiefly limited to the postero-lateral group, but this limitation does not occur in the 
cervical region. Assuming the correctness of the explanation already put rorward, it would appear 
tliat in the cat the upper limbs are more under cerebral control, and their movements less directed 
by peripheral sensory impulses, than is the case with the lower limbs, and hence the complete 
cessation of these impulses is less potent to produce anatomical changes in the anterior ganglion 
The complexity and range of movement of the upper limbs in a cat is certainly much 
greater than that of the lower limbs and indicates a greater degree of dependence on cortical 
innervation. 
Median group 8 
Anterior lateral group 6 
Central (near the spinal cord) z 
Posterior horn 4 
Median group 8 
Posterior lateral group 8 
Anterior lateral group 4 
Most of these on the side on 
which the other roots were 
also cut. 
cells. 
