COMMISSURAL NEURONES 391 
B. On ganglia of operated frogs 
1. Winter frogs with spinal cords destroyed. A first lot of six 
dozen frogs was received on March 20, 1917, and, as the season 
was backward, I have regarded these as winter frogs. Forty-two 
of the frogs were operated by destruction of the spinal cord to the 
second or third vertebra as described above. Thirty-four sur- 
vived the operation and were later injected with methylene blue 
or their sympathetic ganglia removed and stained by the pyridine 
Fig.3 Four autonomic cells and their related spirals and pericellular networks. 
In well stained ganglia the pericellular fibrils appear to form closed networks. 
Methylene blue. X 546. 
silver process. The anterior ganglia were always kept separate 
from the posterior ganglia and the results obtained on each com- 
pared. Degeneration was allowed to continue from nine to 
fifty-four days. 
After nine days’ degeneration methylene blue preparations 
gave normal histological pictures. No sign of degeneration could 
be seen, either in anterior or posterior ganglia. In pyridine 
silver preparations, however, evident signs of degeneration were 
present in the posterior ganglia. Spirals were less numerous 
and many were only faintly stained. Throughout my observa- 
