~The Ciliary Ganglion of Birds. 
By 
F. W. Carpenter. 
(With 2 fig. in the text and Plates XV and XVI.) 
Anatomists are accustomed to assign the ganglia found outside 
the* central nervous system of vertebrates either to the cerebro-spinal 
or to the sympathetic systems of peripheral nerves. Most ganglia fall 
readily into one or the other series, since the evidence furnished by 
their topographical relations, histological structure, and developmental 
history admits of no question as to their classification. There is, never- 
theless, one peripheral accumulation of ganglion cells concerning which 
anatomists cannot yet be said to be in agreement. This is the ciliary 
ganglion of the head, first described by Schacher in 1701, and 
assigned by Arnold in 1831 to the sympathetic system, where, however. 
it has not been allowed to rest in peace. Schwalbe in 1879, after 
extensive anatomical studies embracing all classes of vertebrates, con- 
cluded that the ganglion belonged to the cerebro-spinal series, and that 
the oculomotorius, with which. it is primarily connected, deserved to 
rank as a complete segmental nerve. Two years later W. Krause 
stated his opinion that, while in lower vertebrates the ciliary ganglion 
appeared to be the homologue of a spinal ganglion, in mammals it 
must be regarded as a composite structure, formed in part of cerebro- 
spinal, in part of sympathetic elements. Very recently v. Lenhossék 
(:10, :11) has reached the conclusion that the ganglion, from the 
standpoint of its histological structure, conforms neither to the cerebro- 
spinal nor sympathetic type, but must be regarded as a ganglion sui 
generis. Meanwhile, the original view of Arnold as to its purely 
sympathetic nature has not lacked supporters among recent investigators, 
and especially in the domain of human anatomy has this view held its 
ground (see, for instance, Miiller und Dahl, :10). 
The present investigation of the finer structure of the ciliary ganglion 
in birds has been carried on by means of different methods, the most 
successful of which have been the methylene blue intra-vitam 
