.PROFESSOR ALISON ON THE NERVES OF THE EYEBALL. 79 



have for its office to give to any other, the power of taking on any vital action ; 

 and that the only doctrine on this subject which involves no hypothesis, is that of 

 HALLEE, who regarded every part of the body which is endowed with irritability, 

 as possessing that property in itself, but subject to excitement and to control, of one 

 kind or another, from the nervous system ; and the nervous system as exercising 

 that control chiefly, and in the natural and healthy state probably only, in so 

 far as it is the seat and the instrument of mental act's. 



This doctrine, excluding the larger masses of the nervous system from all 

 share in bestowing the property of irritability or vital energy on muscles, has 

 received, as it seems to me, the only confirmation of which, in the present state 

 of our knowledge, it stood in need, from the experiments of Dr REID, which were 

 laid before the British Association in 1834, and have since been repeated on warm- 

 blooded as well as cold-blooded animals. These experiments prove, that after the 

 irritability of muscles has been, as nearly as possible, extinguished by irritation, 

 it is perfectly recovered by rest, notwithstanding that all their connections with 

 the brain and spinal cord have been cut. 



There is, however, nothing hypothetical or visionary in the assertion as to 

 the nerves, that " Soli in corpore, Mentis sunt ministri;" and, therefore, when 

 we observe that all the great organs of involuntary motion, and among others the 

 iris, have nerves which have passed through ganglia, and when we remember 

 that all those organs are beyond the power of the will, but are peculiarly liable 

 to control from certain involuntary acts of Mind, particularly from Sensations 

 and Emotions, our business is to inquire whether there is any thing in the struc- 

 ture of those parts of the nervous system which can be supposed to unfit them 

 for the one of those offices, and fit them for the other. And if we keep steadily 

 in mind this precise object of our inquiries, we shall find the subject less obscure 

 and intricate than it has often been thought. 



When it is stated that the nerves which pass through the Ciliary Ganglion sup- 

 ply the only muscle in the eyeball, the actions of which are truly involuntary, 

 that all the truly involuntary muscles of the body have in like manner nerves 

 which pass through ganglia, and, farther, that all these ganglia appear, from the 

 most recent and careful examination, to be, like the ciliary ganglion, formed of 

 filaments both from motor and sensitive nerves, it is impossible to doubt, that 

 much of what can be ascertained as to the office of this ganglion in the eye, 

 must be truly applicable to the other ganglia supplying involuntary muscles in 

 the body. 



If we were to assert, however, that all nerves which excite involuntary move- 

 ments in the body, in obedience to sensation or emotion, are ganglionic nerves, 

 or that it is through ganglia only, that these involuntary acts of mind affect the 

 body, we shall be immediately met by various examples of sensations (or the ner- 



VOL. XV. PART I. Y 



