Increased Sensation.
GENUS [I].
With Increased Action of the Muscles.
The actions belonging to this genus are those which are immediately excited by the sensations of pain or pleasure, but which are neither followed by inflammation, nor by convulsion. The former of which belong to the subsequent genera of this order, and the latter to the class of voluntary motions.
The criterion between the actions, which are the immediate consequence of painful sensation, and convulsive actions properly so called, consists in the former having a tendency to dislodge the stimulating cause, which induces the painful sensation; and the latter being exerted for the purpose of expending the sensorial power, and thus dulling or destroying the general sensation of the system. See Class [III. 1].
There is a degree of heat produced in the affected part by these sensitive actions without inflammation, but in much less quantity than when attended by inflammation; as in the latter there is a production of new vessels. See Sect. XXXIII. 2. 3.
Some of the species of this genus cannot properly be termed diseases in their natural state, but become so by their defect or excess, and are here inserted to facilitate the explanation of the others.
SPECIES.
[1]. Deglutitio. Swallowing our food is immediately caused by the pleasureable sensation occasioned by its stimulus on the palate or fauces and is acquired long before the nativity of the animal. Afterwards the pain of hunger previously produces the various voluntary exertions to procure the proper material, but the actions of masticating and of swallowing it are effected by the sensorial power of sensation; which appears by their not being always controulable by the will, as when children in vain attempt to swallow nauseous drugs. See Class [IV. 1. 3. 1]. The masticated food stimulates the palate, which is an organ of sense, into so much action, as to produce agreeable sensation; and the muscles subservient to deglutition are brought into action by the sensation thus produced. The pleasureable sensation is the proximate cause; the action of the fibres of the extremities of the nerves of taste is the remote cause; the sensorial power of irritation exciting these fibres of the nerves of taste into increased action is the pre-remote cause; the action of the muscles of deglutition is the proximate effect; the pushing the food into the stomach is the remote effect; and the nutrition of the body is the post-remote effect.
Though the muscles subservient to deglutition have their actions previously associated, so as to be excited into synchronous tribes or successive trains, either by volition, as when we swallow a disagreeable drug; or by sensation, as when we swallow agreeable food; or by irritation, as when we inattentively swallow our saliva; yet do all those three kinds of deglutition belong to the respective classes of volition, sensation, and irritation; because the first links of these tribes or trains of muscular action are excited by those sensorial powers, and the associated links, which accompany or succeed them, are excited by the combined powers either of volition, or of sensation, or of irritation, along with that of association.