86 SYDNEY E. JOHNSON 
ganglia, various possibilities have been suggested. These have 
been considered by Langley (’03), and his observations have 
been often referred to. Langley has produced much evidence 
against the existence of such connecting neurons. His results 
and conclusions which have been reviewed recently by Ranson 
and Billingsley appear to be supported and confirmed by an 
increasing amount of purely anatomical investigation. If com- 
missural neurons are present their terminations would be expected 
to form some part of the intercellular plexus of the sympathetic 
ganglia, but upon degenerative section of the cervical trunk, 
Ranson and Billingsley (’18 a) found that the fine axonic rami- — 
fications of the intercellular plexus completely disappeared, 
indicating that it is derived wholly from ascending preganglionic 
fibers. Two distinct functional types of autonomic cells such 
as might be anticipated from Dogiel’s report could not be demon- 
strated by Carpenter and Conel (’14) on the basis of cell structure. 
The writer (18) has produced experimental evidence against the 
occurrence of commissural neurons in the sympathetic ganglia 
of the frog. 
Suggesting the occurrence of commissural neurons are obser- 
vations of a rather fragmentary character which, however, must 
be considered. The more important of these observations have 
been reported by v. Lenhossék, Dogiel, and Huber. 
Lenhossék’s (’94) report is substantially to the effect that he 
observed, in Golgi preparations of fourteen-day chick embryos, 
sympathetic fibers entering a sympathetic ganglion from the 
periphery and there terminating in simple end-brushes. The 
fibrillae of these end-brushes are said often to terminate on 
autonomic cells in small end bulbs. 
Observations of a somewhat similar nature are recorded by 
Huber, who, in his 1897 ‘‘Lectures on the Sympathetic Nervous 
System” wrote that ‘ain methylen-blue preparations of the 
ganglia of the chain taken from mammalia and birds, I have 
often observed a free ending of branches of non-medullated 
nerve fibers in sympathetic ganglia.”’ These endings are different 
from those described by v. Lenhossék, inasmuch as they are on 
the dendrites of sympathetic neurons rather than on the cell 
