SYMPATHY. 



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supposition of some such similar consent 

 between different or even distant parts in the 

 same person. 



Motions or sensations caused in certain 

 parts, in consequence of a primary irritation 

 of other and distant parts, are of the sym- 

 pathetic kind. These motions or sensations 

 are produced in, as it were, an indirect or 

 circuitous manner, or one different from that 

 in which they are ordinarily excited. 



Thus a stimulus to the olfactory membrane 

 causes a peculiar affection of the sense of 

 smell, and occasions that depression of the 

 heart's action, from which results a state of 

 syncope. Or another affection of the same 

 sense causes a suddenly increased action of 

 the salivary glands. 



If we analyse any one of these examples of 

 sympathetic actions, it will appear that three 

 circumstances may be noticed in the produc- 

 tion of the phenomena .- 1st, the primary 

 exciting cause, which may be an object pre- 

 sented to the mind through one of the organs 

 of sense, or causing an impression upon any 

 sensitive nerve, and therefore upon some part 

 of the centre of sensation ;. Sndly, the part 

 affected directly by this primary stimulus ; 

 and, Srdly, the action or sensation resulting 

 from the affection of this part. 



Many other sensations or motions may be 

 enumerated besides those above referred to, 

 whether occurring in health or in disease ; 

 and we shall give examples of these before we 

 discuss this subject further. 



The examples of sympathetic sensations 

 which may be adduced are chiefly of the mor- 

 bid kind. Pain is felt at a certain part, in 

 consequence of an irritation in another part 

 distant from it, and apparently altogether 

 unconnected with it. A familiar instance of 

 this is pain in the knee from disease of the 

 hip-joint. So marked in some instances is 

 the pain in the knee r and so. much has it ab- 

 sorbed the patient's attention, that the real 

 seat of the disease has been overlooked, and 

 the remedies been applied exclusively to the 

 knee. Pain in the right shoulder, from 

 disease of the liver, is a sympathetic sensa- 

 tion of similar kind ; and sometimes the 

 hepatic irritation causes pain over a more 

 extensive surface. Whytt mentions, that, in 

 two cases of suppuration of the liver,, he had 

 seen the patients " affected with a numbness 

 and debility of the right arm, thigh r and leg." 

 Sometimes both shoulders are the seat of 

 pain, from hepatic irritation. 



The peculiar sensations felt in the teeth 

 from a noise which grates upon the ears, is 

 sympathetic of the irritation of the auditory 

 nerve. Practitioners are well aware how many 

 morbid sensations in parts remote from the 

 intestinal canal may be cured by the removal 

 of scybala or other accumulations from it. 

 Painful affections of the nerves of the face, 

 and of other parts, are often due to. a cause 

 of this kind. The irritation of a stone in the 

 bladder gives rise to pains in the thighs, or 

 to itching at the end of the penis ; and 

 uterine irritation, whether from disease or 



from the enlargement of that organ in con- 

 nection with the early stage of pregnancy, 

 causes similar pains in the nerves of the 

 thighs. 



Headache and defective vision are fre- 

 quently produced by disordered stomach. A 

 draught of very cold water, or ice, taken 

 quickly into the stomach, may occasion acute 

 pain in the course of either frontal nerve. 

 This same nerve on one side is frequently the 

 scat of pain after the imprudent use of acid 

 wines or other fermented liquors. 



Movements, excited by the operation of a 

 stimulus applied at a distance, form a large 

 proportion of the instances of sympathetic 

 phenomena. All the ordinary physical ner- 

 vous actions in which motions are excited by 

 stimulating a sentient surface, may be regarded 

 as examples of sympathetic actions.* The 

 contraction of the iris upon the application of 

 the stimulus of light to the retina, or of the 

 pharvngeal muscles by stimulating the mucous 

 membrane of the fauces, are instances in point 

 where the stimulus acts indirectly upon the 

 contracting fibre.. Nothino; is more sure than 



o O 



that in these instances the change wrought by 

 the stimulus in certain sentient nerves, travels 

 by a circuitous route through a nervous centre 

 to the muscles which are called into action. 

 Akin to these actions are the forcible respira- 

 tory movements which may be excited by ir- 

 ritation of the tracheal membrane, as coughing; 

 or sneezing, by stimulating the nasal mem- 

 brane ; or vomiting, by irritating the fauces. 

 Spasmodic affections are often instances of 

 morbid actions in sympathy with intestinal 

 irritation, or the irritation of teething in chil- 

 dren. Partial or general convulsions are very 

 frequently due to either or both these causes. 

 We have known the most violent opisthotonos 

 co-existing for a considerable time \\ith the pre- 

 sence of lumbricoid ascarides in the intestine ; 

 but ceasing immediately on the removal of the 

 worms. Vomiting is commonly sympathetic 

 of diseased kidney, or of the passage of a 

 calculus along the ureter; or of the passage 

 of a gall-stone along the gall duct ; or it may 

 be induced by the introduction of a catheter 

 into the urethra. 



The consentaneous action of symmetrical 

 parts is no doubt due to a similar cause to 

 that by which most of the sympathetic actions 

 are excited, and more especially in those parts 

 where symmetry of action is constant, al- 

 though liable to be interrupted by the influence 

 of the will. 



A distinct class of sympathetic actions con- 

 sists of those in which certain parts enlarge 

 or become developed simultaneously with, and 

 to a certain extent in effect of, the increase 



* It has been remarked, that the term " sympa- 

 thetic actions " involves a contradiction. But it 

 may be observed, that the contraction of the mus- 

 cles, on which the action depends, is only the 

 natural mode in which that class of vital organs can 

 manifest their consent with certain states of nervous 

 centres, or of sensitive nerves. The action is the 

 result of the state which the muscle assumes in 

 sympathy with the stimulated nerve. The con- 

 tradiction is therefore apparent, not real. 



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