108 HENRY O. FEISS 
sal and plantar flexion of left paw and ankle, and plantar flexion of right 
seems possible with only anterior columns open. 
Experiment 86. (Figs. 10 and 11.) External popliteal paralysis on 
both sides due to damage in middle 6th and lumbar segments and roots 
attached. Almost complete paralysis of internal popliteal on right 
and not on left corresponds to lesion in upper 7th lumbar segment. 
Loss of point and heat-pain sensation on right and not on left explained 
by lesion in right half of cord in 5th lumbar segment. The difference 
in damage to grey matter in lower 6th and upper 7th lumbar segments 
must account for preservation of left knee jerk. As internal popliteal 
is good on left and its centers are in upper 7th lumbar segment, impulses 
from the brain to its synapses must have passed through the marginal 
portion of the anterior column in the segment above. 
Experiment 69. (Figs. 12 and 13.) The difference between the right 
and left anterior horn involvement in the upper 7th might explain the 
weakness of the right external popliteal. Lesion in 6th lumbar segment 
suggests a gap between upper and lower leg centers. This lesion seems 
to have had no effect on either knee jerk or on sensations, suggesting 
that these latter must have entered through upper 6th rootlets or higher. 
As the centers presiding over control of right paw may be presumed to 
be below the 5th lumbar segment, the extent of the lesion might denote 
that such control was cut off on that side. Therefore, as the dog used 
the paw quite well (except for the external popliteal weakness mentioned) 
it is possible that impulses crossed from the other side, where the lat- 
eral column was good. 
Experiment 65. (Figs. 14 and 15.) The extensive paralysis of the 
left leg and paw together with loss of knee jerk, best accounted for by 
severe root involvement, while the weakness in the right upper leg is 
accounted for by damage to anterior horn in lower 6th lumbar segment 
and some of the 6th anterior root filaments. 
Experiment 75. (Figs. 16 and 17.) Here permanent flexure of right 
hip and stiffness of knee, perhaps due to weakness of gluteals and ham- 
strings respectively, caused by damage of 5th, 6th and 7th anterior 
roots. The lower leg paralysis explained by Jesion in 7th lumbar and 
lst sacral segments. Loss of right knee jerk explained by damage to 
6th posterior root. 
Experiment 70. (Figs. 18 and 19.) The lesion in lower part of 5th 
lumbar segment involved entire cord, practically acting as a trans-sec- 
tion. This accounts for loss of control and spasticity of hind parts, 
and places most of leg centers below that segment. It is likely that 
preservation of knee jerk, anal reflex and control of sphincters is due to 
sparing of centers below middle 6th lumbar segment (the anterior roots 
being also destroyed above that level). 
Experiment 72. (Figs. 20 and 21.) The lesion in upper 5th, 6th and 
7th lumbar segments, with the corresponding anterior root damage ac- 
counts for loss of control of hind parts, including point sensation, knee 
jerks and sphincters. 
Experiment 68. (Figs. 22 and 23.) Impairment of control of motion, 
point and heat-pain sensation of tail, together with impairment of anal 
