ee 
ganglion. Langendorff, himself, observed that after death by bleeding 
the ciliary ganglion of mammals lost its capacity to transmit impulses 
before the short ciliary nerves became inactive. This he believed to be 
due to the intercalation of ganglion cells between the fibers of the oculo- 
motorius and the nervi ciliares breves. The condition is typically sym- 
pathetic. When he experimented upon a duck he obtained quite different 
results. The ciliary ganglion, deprived of blood, continued for about 12 
minutes to permit the passage of impulses originating in the third nerve. 
When stimulation of the latter no longer affected the iris, stimulation 
of the nervus ciliaris crassus, i. e., a postganglionic nerve, was equally 
ineffective. Langendorff’s conclusion was that the fibers of the oculo- 
motorius in birds do not terminate in the ciliary ganglion, since the 
physiological evidence points to the continuity of the transmitting 
apparatus. This he believed to be effected by means of bipolar ganglion 
cells, each of which sends one process caudal into the oculomotor nerve, 
and the other cephalad into the short ciliaries. In this view he was 
supported, as has been mentioned, by the anatomical findings of Ret- 
zius and Holtzmann. 
In the light of our present knowledge of the histological structure 
of the bird’s ciliary ganglion its exceptional behavior is readily explained 
in a quite different manner. The oculomotor neurites unquestionably 
terminate in the ganglion, but their grasp, so to speak, on the next set 
of neurones is, by means of calyx endings, so intimate and comprehen- 
sive that a practically uninterrupted path is offered for the nervous 
nnpulse. The ganglion, therefore, resists nicotin and bleeding, while 
sympathetic and mammalhan ciliary ganglia, with less binding synapses 
between their neurones, yield readily to these influences. 
Pumetioms of the Pibéer Bumdies emuerime the Oilrary 
Ganglion. In Figure 15 I have represented in a diagrammatic way 
the histological relations between the ganglion and the fiber bundles 
connected with it. It can there be seen at a glance that we have to 
do with two systems of neurones, an oculomotor and a trigeminal, each 
of which contains pre- and postganglionic elements, the cell-bodies of 
the latter being situated in the ganglion. If it be admitted that the 
foregoing account warrants this conception of the anatomical relations, 
we may pass to the consideration of the physiological significance of 
the tracts represented. 
As to the function of the oculomotor system there can be no question. 
Investigators are agreed that stimulation of the third nerve causes 
contraction of the pupil. Therefore the fibers entering the ganglion from 
the oculomotorius, and the postganglionic ciliary neurones connected with 
them, are efferent or motor, and subserve the function of pupil constriction. 
