1852.] OF THE ROYAL INSTITUTION. 151 
females ; sa that it cannot be fairly set down as a variety of ‘ hysteri- 
cal’ disorder. Generally speaking, those who have most of the 
power of voluntary abstraction are most easily affected in this mode; 
more especially if, at the same time, they are of an excitable or ima- 
ginative temperament. 
It now remains to enquire, whether any such Physiological ac- 
count can be given of this state, as shall enable us to refer it to 
any of the admitted laws of action of the Nervous system. This, 
the Lecturer stated, was the point which he was most desirous of 
elucidating ; and in order to prepare his auditors for the reception 
of his views, he gave a brief explanation of those phenomena of 
‘reflex’ action (now universally recognized by Physiologists), in 
which impressions made upon the nervous system are followed by 
respondent automatic movements. Such movements have hitherto 
been distinguished into the excito-motor, which are performed, without 
the exciting impression being necessarily felt, through the instru- 
mentality of the Spinal Cord and the nerves connected with it; and 
the sensori-motor, in which sensation necessarily participates, the 
respondent motions not being executed unless the impressions are felt, 
and their instrument being the chain of Sensory Ganglia (collectively 
constituting the ‘sensorium’ ) which lies between the Spinal Cord 
and the Cerebrum, and is intimately connected with both. The au- 
tomatic movements of breathing and swallowing, which continue 
during a state of profound insensibility, are examples of the former 
group; whilst the start upon a loud sound, the closure of the lids 
to a flash of light, or the sneezing induced by dazzling of the eyes, 
as well as by irritation in the nasal passages, are instances of the 
latter. The whole class of purely emotional movements may be 
likened to these; for in so far as they are involuntary, and depend 
upon the excitation of certain states of mind by external impressions, 
they must be considered as ‘ reflex’ in the general sense of that 
term, 
Now the usual modus operandi of sensations is to call forth ideas 
in the mind; and these ideas, associated or not with emotional states, 
become the subjects of intellectual processes, which result at last in 
a determination of the Will. The movements which we term volun- 
tary or volitional differ from the emotional and automatic, in being 
guided by a distinct conception of the object to be attained, and by a 
rational choice of the means employed. And so long as the Volun- 
tary power asserts its due predominance, so long can it keep in 
check all tendency to any other kind of action, save such as ministers 
directly to the bodily wants, as the automatic movements of breathing 
and swallowing. 
The Cerebrum is universally admitted to be the portion of the 
nervous system, which is instrumentally concerned in the formation 
of ideas, the excitement of the emotions, and the operations of the 
intellect ; and there seems no reason why it should be exempted 
from the law of ‘ reflex action’ which applies to every other part of 
