COMMISSURAL NEURONES 403 
pericellular baskets in the sympathetic ganglia of the frog are of 
cerebrospinal origin (preganglionic fibers), 2) that many of the 
spirals and baskets in the posterior ganglia are the endings of 
preganglionic fibers which join the sympathetic trunks at a 
much higher (more anterior) level (this assumption is necessary 
to explain the progressive dropping out of the spirals and net- 
works from the anterior to the posterior ganglia after degenera- 
tion caused by destruction of the spinal cord); 3) that com- 
missural neurones or endings do not occur in the sympathetic 
ganglia of the frog. 
To what extent the results of the observations reported above 
may be applicable to the sympathetic ganglia of higher verte- 
brates remains for future investigation to disclose. It has been 
asserted that the general scheme (of autonomic relations) is 
probably the same in all vertebrates. It is my belief, however, 
that this assertion should not be interpreted to exclude com- 
missural connections from the sympathetic ganglia of all verte- 
brates solely on the basis of findings in the sympathetic ganglia of 
Amphibia. Considered, however, in connection with results 
obtained on higher vertebrates by Langley, Carpenter and Conel, 
Ranson, and others, the evidence here presented appears to me 
to afford additional weight to the argument against the om- 
missural neurone hypothesis. 
