256 



KNOWLEDGE. 



July, 1913. 



diet and the ordering of a couple of pills, has more 

 or less satisfied a large proportion of the profession, 

 if not the public. It is strange that this should 

 be so, as the symptoms of an ordinary bilious 

 attack are not at all similar to those of well- 

 marked and true sea-sickness. Let us therefore try 

 to find if similar symptoms are produced under other 

 circumstances. 



If the body be rotated rapidly, and an attempt be 

 then made to walk, it will be found that staggering 

 has been produced, clearly proving that coordination 

 has been interfered with. This is owing to the 

 endolymph having been subjected to unusual move- 

 ment. Nor. if rotation be continued, is incoordination 

 the only symptom : headache, giddiness, slight double- 

 sight, rapid pulse, flushing followed by chilliness, and 

 distinct nausea will in turn be experienced — these 

 being produced by the irritated endings of the 

 auditory nerve conveying sensation to brain and 

 stomach. If we compare the above set of symptoms 

 with those of sea-sickness a marked similarity is 

 at once seen. 



It is a well-known fact that some children are 

 unable to use a swing owing to nausea, giddiness 

 and headache being caused, while other children 

 and many adults suffer in a minor degree. Here, 

 again, the endolymph is subjected to an unusual 

 motion as compared to that caused by our ordinary- 

 movements. 



There are also those who experience when on a 

 switchback railway or a water-chute one or more of 

 the above symptoms, undoubtedly due to a similar 

 cause. 



The high dive and violent horseback exercise have 

 been known to produce in those unused to such 

 sports disagreeable effects of a nature akin to those 

 of mal-de-mer. 



In my own personal experience, and that of most 

 other sufferers, it is the pitching motion that pro- 

 duces the most severe form of sea-sickness. In 

 a rolling ship the nausea and vomiting are much 

 less and of shorter duration. Have we in this fact 

 any proof of the endolymph theory ? Undoubtedly ; 

 since it is the fluid in the vertical canals that is 

 affected in pitching, and, as they are two to one, we 

 naturally suspect double the effect. In rolling, on 

 the contrary, the fluid in two canals is practically at 

 rest, only one — the horizontal — having its fluid level 

 and pressure on its walls much changed. 



The proportion of those who do not overcome 

 sea-sickness, if long on board ship at one time, is 

 small ; usually, after a more or less prolonged 

 apprenticeship, the nerve filaments become accus- 

 tomed to the motion. If, however, the ocean be 

 exchanged for the sea or channel, where the waves 

 are short, and the liner of twelve thousand or more 

 tons replaced by the boat of eight hundred tons, 

 sickness in many cases will return, even in the case 

 of old seamen. 



Such a fact cannot, I think, be explained on any 



other hypothesis of the causation of the malady 

 than the endolymph theory; accept that, and the 

 explanation is easy. The fluid, which has become 

 accustomed to one motion, is subjected to another of 

 a different character, and the new one produces its 

 effect. Should the circumstances be reversed and 

 the large ship substituted for the small one, sickness 

 will not, as a rule, be produced ; since the motion of 

 the former is better borne, the endolymph being 

 more agitated by short seas on a small boat. A 

 person who suffers under these conditions is not 

 necessarily a bad ocean traveller. 



Seasickness produced during sleep is a stumbling- 

 block to those who believe that the optic nerve is the 

 medium for sensation producing sickness, and is 

 difficult to explain by any process of reasoning but 

 the one. The endolymph is, of course, influenced 

 by motion whether the person is awake or asleep ; 

 the effect, however, is considerably lessened by the 

 recumbent position. Hence it is a wise precaution, 

 advocated by many who do not grasp the true 

 reason, for a person liable to mal-de-mer to lie down 

 when starting on a short passage. Such advice is 

 obviously not of much use to those starting on a 

 long sea voyage, with continued bad weather, unless 

 supplemented by treatment. 



Some persons after a short voyage, on which they 

 have experienced bad weather, continue to feel the 

 motion after landing. This is a very direct proof 

 of the origin of the sensations felt on board ship, the 

 explanation being that the fluid in the canals has 

 accustomed the nerves to the feeling of the motion, 

 which they do not lose for some time. 



It is found that, however ill a person may be, the 

 moment the ship runs into perfectly calm water all 

 symptoms vanish, except perhaps the sensation just 

 referred to. Such would not be the case were the 

 stomach seriously at fault, but is explained by the 

 action of our " spirit-level." 



It is a curious fact that, in these days of scientific 

 accuracy, the bromides are sometimes prescribed by 

 those who speak and write of sea-sickness being of 

 gastric or hepatic origin. I can see only one legiti- 

 mate reason for prescribing bromides — namely, belief 

 in the nervous origin of the ailment — and I would 

 point out, as a further proof of the pathology 

 advanced above, the very direct effect they have 

 in subduing symptoms. 



I am not aware that such weight of practical and 

 scientific proof can be brought forward in support of 

 any other theory of the pathology of sea-sickness. 

 The endolymph causation, indeed, can hardly be 

 regarded as theory ; the evidence of its being the 

 true cause is, short of ocular demonstration, to my 

 mind complete. Gastric symptoms are certainly 

 prominent, but not more so than in many con- 

 ditions where they are admittedly secondary. The 

 symptoms referable to the semicircular canals and 

 the brain are so evident that there is no mistaking 

 them, though, to a great extent, they have been 

 ignored in the past. 



