COMMISSURAL NEURONES 393 
derived from cerebrospinal fibers entering the sympathetic trunks 
at a higher level than that to which the spinal cord was destroyed, 
or else endings of commissural neurones with cell bodies located 
outside of the spinal cord. In the posterior ganglia of the same 
specimens (pyridine silver preparation) no complete spirals have 
been observed, although an occasional darkly stained pregan- 
glionic fiber could be found. These fibers stand out in sharp con- 
trast to the lightly stained postganglionic fibers. A typical 
histological picture for the posterior ganglia is shown in figure 9. 
Fig. 6 Section of an anterior ganglion of a specimen injected with methylene 
blue forty-six days after destruction of the spinal cord. Many spirals can be 
found in the anterior ganglia. XX 358. 
Fig. 7 From a posterior ganglion of the same specimen (as fig. 6). The 
specimens show distinct evidence of degeneration of preganglionic fibers. Meth- 
ylene blue. X 358. 3 
Pyridine silver preparations made after a degeneration period 
of fifty-six days gave histological pictures identical with those 
just described. 
The remaining frogs were injected with methylene blue after 
periods of 46, 48, 54, and 56 days. All of these gave similar 
results. Degeneration continued beyond forty-six days did not 
appear to affect the results obtained. The anterior ganglia of 
all of these specimens show uniformly a large number of spirals 
and pericellular baskets. Figure 6 shows a typical section. 
