496 S. WALTER RANSON 
serious objection to this experiment, since previous to the removal 
of the roots and ganglia on the left side he had torn out both 
sciatic nerves. Hence there was present in the pelvis the torn 
central fragments of the right sciatic nerve. So great was the 
regenerative energy of this right sciatic stump that it was found 
at autopsy that its fibers had grown out of the right great sacro- 
sciatic foramen and established an anatomically demonstrable 
connection with the right peripheral stump. Under these cir- 
cumstances it is hard to convince oneself that a few regenerated 
fibers may not have taken a different course, grown across the 
anterior surface of the sacrum out of the left great sacro-sciatic 
foramen and down to the left peripheral stump. Bethe’s other 
experiments with removal of the roots were negative, a fact 
which he can only explain as due to the poor state of the general 
health of the dogs upon which so mutilating an operation had 
been performed. 
To meet the objections of Langley and Anderson he performed 
two experiments in which several months after the tearmg out of 
the sciatic he tried to cut all possible connections with the spinal 
cord and six days after the secondary operation still found 
undegenerated medullated fibers in the peripheral stump. But 
in one of these cases it is clear that all possible central connec- 
tions were not divided. In this case the second operation con- 
sisted in cutting the roots associated with the nerves going to 
the leg, and as autopsy showed, he failed to cut the 1 S. root. 
In the other experiment the secondary operation consisted in 
(1) cutting the femoral and obturator near the pelvis, (2) cutting 
the 1, 2, and 3 S. nerves at their exit from the intervertebral 
canal, and (3) ligature and division of the tissue at the normal 
point of exit of the sciatic nerve. Since in the primary opera- 
tion the 6th and 7th L. roots and ganglia had been torn out. 
with the sciatic, this control seems to have been fairly complete. * 
It is plain however that this experiment was very complicated 
and gave opportunities for error in the operations and subse- 
quent observations. In the opinion of the present writer the 
positive results of Bethe in these three cases are to be attributed 
to his habit of tearing out the sciatic nerve, producing a lesion 
