SNEEZING, SEA-SICKNESS, FAIN 429 



SNEEZING, SEA-SICKNESS, PAIN 



By ALEX HILL, M.D., F.R.C.S. 



SOMETIME MASTER OF DOWNING COLLEGE, CAMBRIDGE 



PHYSIOLOGISTS can not lay claim to a theory of pain. Even 

 definition is difficult. The distress of bodily wants overlaps 

 pain on the one side; fear, anxiety and similar mental states overlap it 

 on the other. Excessive stimulation of certain organs of special sense, 

 particularly those for touch, temperature and hearing, leads up to it. 

 If an attempt be made to isolate, in thought, the effect in consciousness 

 to which the term " pain " properly applies, it may be said to be the 

 awareness of something amiss in some part of the body, irrespective of 

 the testimony of either of the special senses. It is a modification of 

 consciousness, not a part of its content. We have learned to associate 

 the receipt of the modifying influence through particular nervous 

 channels, with its provenance, just as we have learned to associate 

 sensations of touch conveyed by particular nerve-fibers with the con- 

 tact with external objects of particular regions of the skin; but such 

 topognosis is no more innate in the one case than in the other. It is 

 the product of self-investigation, and is based either upon the testi- 

 mony of the eye or upon experiments in moving the hand to the spot. 

 Hence in the case of organs which are out of sight and out of reach 

 topographical guidance is unobtainable. Since we can have no knowl- 

 edge of its seat, the pain is referred to some accessible part of the seg- 

 ment of the body in which it occurs. A gulp of very hot water, on 

 reaching the closed sphincter muscle of the stomach — the valve which 

 must open before it can pass from gullet into stomach — gives ri?e to 

 pain which seems to have its seat in the skin over the lower end of the 

 breast-bone. In the same way disease of the various viscera gives rise 

 to pain and tenderness of areas of the skin of the segments of the 

 body in which the nerves of the viscera join the spinal cord. 



From a physiological standpoint " pain " and " sensation " are 

 antithetical terms. Sensations inform. Pain is a state of conscious- 

 ness which masks sensation. Sensations are transient. Their apparent 

 prolongation is due to repetition. They are vibratory. Pain is a 

 condition, slowly set up, slow to disappear. Even the briefest pain is 

 long as compared with the constituent unit — a nerve wave — of sensa- 

 tion. It is of the very essence of sensation that it has quality or modal- 

 ity; the informing value of any given sensation depends upon its ex- 

 cluding all other forms of stimulation. The sensation of a bright red 

 spot of light is not susceptible of confusion in place or quality with 

 other visual sensations. Still less is it liable to be mistaken for a sen- 

 sation of hearing or of taste. Pain has no modality. If it may be 



