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 

 fibi-es 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 hyperesthesia 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, &c, spasm 

 of some of the cerebral arteries has taken place, producing temporary 

 blindness, deafness or aphasia, or which wera 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 

 Irritation," words appropriately describing the condition here present. 

 He says: — " The abnormal excitation of the cerebro-spinal system, 

 causes its tirst 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 Eerrier and the experi- 

 ments of Van der Becke, Callenfels, Nathnagel, and Krishaber have 



