PHYSIOLOGY. 



Other modes of sympathetic connection, 

 without the immediate concurrence of 

 nerves, are poi.Ht-d out by physiologists : 

 as by blood vessels, in the sympathies of 

 the uterus and breasts; from the anasto- 

 moses of the epigastric and internal mam- 

 mary arteries ; by lymphatics ; by analo- 

 gy of the respective functions, as the 

 sympathy of the lungs and common inte- 

 gument-. 



Habit, or the reiterated repetition of 

 certain acts or motions, has a powerful in- 

 fluence in the animal economy. But it 

 operates much more decidedly on the 

 animal, or exterior, than on the organic, 

 or interior life. It has the effect of di- 

 minishing the sensibility of our organs, 

 as appears from the effect of using pes- 

 saries in the vagina, catheters in the ure- 

 thra, &c. Relative pleasure or pain are 

 brought by the influence of this principle 

 to the state of indifference. Things are 

 agreeable or disagreeable, by a compari- 

 j^on between the impression they make 

 on. the senses and the state of mind re- 

 ceiving that impression. Hence the im- 

 pressions produced on our organs in the 

 cases just mentioned, although at first 

 painful, are soon disregarded. Pleasant 

 sensations are the same. The cook and 

 the perfumer are not alive to the enjoy- 

 ments which they procure for others. 

 The pleasing emotions connected with 

 the sight and hearing are soon rendered 

 obtuse by repetition ; and any pleasure 

 constantly repeated produces the same 

 series of feelings ; viz. pleasure, indiffe- 

 rence, satiety, and even aversion. The 

 mind is the centre of these changes. It 

 institutes a comparison between the ac- 

 tual sensation and the preceding impres- 

 sions, and in proportion to the difference 

 between these will be the vivacity of the 

 present impression. It belongs, there- 

 fore, to the nature of pleasure and pain 

 to destroy themselves, and to cease to ex- 

 ist because they have existed. The art 

 of prolonging the duration of our en- 

 joyments consists in varying their sour- 

 ces. 



Habit, however, which deadens sensa- 

 tion, augments and brings to perfection 

 the judgment. 



Most of the functions of the organic 

 life are removed from the dominion of 

 habit ; viz. circulation, respiration, &c. ; 

 yet the influence of this principle is 

 unquestionable in some parts of the or- 

 ganic functions, as the urinary secretion, 

 evacuation of feces, hunger and thirst, &.c. 



Voluntary Motions and Muscular Jlction. 

 Having already gone over the subject 



of sensation, one of the offices of the 

 nerves, the other, motion, remains for 

 consideration. The motions of the body 

 have been commonly divided into two 

 classes, the voluntary and involuntary. 

 The action of the heart, stomach, and in- 

 testines, &c. exemplifies the latter ; while 

 the former are the actions of almost all 

 the other muscles of the body. Some 

 are of a doubtful nature, as those of re- 

 spiration, of the ossicula auditus, and the 

 cremasters. Different physiologists as- 

 sign these to one of the above classes, or 

 to a mixed division. 



The arrangement is not unexceptiona- 

 ble. There are few functions entirely 

 free from the operation of the will, if we 

 consider the connection of the imagina- 

 tion and passions of the mind with that 

 power : as, on the contrary, many muscu- 

 lar motions, which were originally arbi- 

 trary, become by the force of habit quite 

 involuntary. Thus we can hardly bend 

 the little finger without the ring fin- 

 ger; and cannot help winking, if a per- 

 son brings his finger rapidly towards 

 our eye, although we are certain that 

 he will not strike us. Again, mus- 

 cles which usually obey the will, refuse 

 obedience under circumstances; hence 

 the difficulty of describing a circle with 

 the hand arid foot of the same side in op- 

 posite directions, of moving the two 

 hands with an opposite circular motion, 

 &.c. Numerous instances might be quot- 

 ed of the power of the will over motions 

 that are usually involuntary; we shall 

 merely mention the fact, supported by 

 the personal testimonies of Drs. Barnard 

 and Cheyne, of an English officer who 

 could influence the action of his heart 

 and arteries (" Treat, on Nervous Dis- 

 eases," p. 307.) Perhaps these pheno- 

 mena may be accounted for by a reaction 

 of the sensorium, excited by a mental 

 stimulus. 



We may observe of the voluntary mo- 

 tions in general, that they form the chief 

 character that distingiusb.es the animal 

 and vegetable kingdoms. No plant has 

 yet been discovered that seeks its food 

 by voluntary motion ; nor, on the contra- 

 ry, is any animal known, that does not 

 either possess a power of locomotion, or 

 at least procure its food by the volun- 

 tary motion of some organ or member. 



These motions in our own bodies shew 

 the very complete harmony between the 

 mind and the material fabric, as we shall 

 readily admit, when we observe the won- 

 derful celerity with which the fingers of 

 the violin player, or the organs of speech 



