70 PROCEEDINGS OF THE CANADIAN INSTITUTE. 
thence the optic nerve. Thus, with the light we have the special 
irritant applied to this nerve of a special sense; and, as proved 
anatomically as well as by physiological experiments, this nerve 
reflects its impression along the third (3rd) nerve to the iris, through 
the ophthalmic ganglion, and, as we know, instantaneous iris con- 
traction is the result. But the impression reflected upon this gang- 
lion has for us the highest interest. In it are ganglion cells with 
fibres connecting with other sympathetic ganglia. Now, however great 
or little may be the optic sensibility here, we are certain of one thing 
in these cases, and that is of an extreme hyperaesthesia of the gang- 
lionic nervous system. Since externally in the changes of the 
iris, we can see the proof of the above supposition, it seems logical 
for us to assume that the sensation reflected from the optic nerve 
creates upon the ganglionic system such an impression that it is 
communicated to the vaso-motor centre—seated in the medulla 
oblongata—of the cerebral arteries ; and that thence is communicated 
an irritation which causes an instantaneous contraction of the cere- 
bral arteries, (possibly also by the irritation supplied to the depressor 
ganglion of the heart,) thus creating an anaemia, an abeyance of 
cerebral functions, and as a consequence the hypnotic state. This 
hypothesis seems quite the same as the one by which Ferrier accounts 
for related cases, where from emotional states, as anger, &e., spasm 
of some of the cerebral arteries has taken place, producing temporary 
blindness, deafness or aphasia, or which were relieved by the use 
of the magnet overcoming the spasm. We must not forget to note 
as a factor in this hypnotizing process, that in all such subjects the 
will-power has been passing into abeyance, since we have already seen 
that in proportion, as this is absent the spinal, and certainly the 
sympathetic, hyper-excitability is increased. 
Here again let me quote from M. Jaccoud on ‘“ Cerebro-Spinal 
Trritation,” words appropriately describing the condition here present. 
He says:—‘‘ The abnormal excitation of the cerebro-spinal system, 
causes its first effects to be felt upon the vaso-motor system, whose 
impressibility is so readily shown by the instantaneous production of 
pallor and of blushing, whence an anaemia or rather secondary 
ischaemia, both of brain and cord, which increases the disorder of 
excitability and transforms it into a persistent condition of irritable 
feebleness. Both clinical facts as shown by Ferrier and the experi- 
ments of Van der Becke, Callenfels, Nathnagel, and Krishaber have 
