R. M. Bache on Sea-sickness. 21 



If such effects as those just described in the case of riding in 

 a carriage can nauseate, when they are produced by compara- 

 tively slight changes in *' the habitual conception of contrasted 

 effects of motion " it is not surprising, that the effect of motion 

 at sea should bring the great and continuous nausea called sea- 

 sickness. The motions of a ship vary infinitely. As soon as a 

 certain kind of motion has lasted for a long time, the voyager 

 becomes accustomed to it, and he has no more tendency to become 

 nauseated, than has the man accustomed to a carriage. He may, 

 however, become sick again, if the motion should vary, and yet 

 not be increased. A person habituated to the sea, may remain 

 ashore for a long time, but his senses readily accommodate 

 themselves again to conditions once understood. It is true, 

 that even old sea captains are sometimes afflicted by sea-sick- 

 ness, but this does not invalidate the theory which I have ad- 

 vanced. There are temperaments so predisposed to sea-sick- 

 ness, that the inuring process has to be perpetually renewed. I 

 do not assert, that the same amount of experience at sea, gives 

 the same immunity to each person. The causes which I have 

 mentioned as superinducing sea sickness affect every one, but 

 the capability of resisting it varies with every temperament. 

 There are individuals who never become sea-sick — that is to the 

 extent of succumbing to nausea — but they undergo the same 

 process of education of the senses. The difference between 

 these persons and those who do succumb, is that their organi- 

 zations in physique and temperament enable them to resist 

 the inclination to nausea and the education of the senses is com- 

 pleted before nausea has been able to overcome them, although 

 it always attacks. There is no one, who in a first experience at 

 sea, is not disposed to nausea, but there are some few persons, 

 who possess such organizations, that with the aid of a firm de- 

 termination to resist an attack of sea-sickness they are enabled 

 to escape it, and to pass the ordeal of the novel motion at sea 

 without manifest inconvenience. 



At sea, motion immediately nauseates, even when it is much less 

 than may be experienced in a swing without the slightest impres- 

 sion. In a swing, motion is comparatively regular. It requires 

 little education of the senses to enable them to keep pace with 

 each other. The evidence of the sight is nearly the same as that 

 of the feeling. If a person in a swing is blind, or keeps the eyes 

 shut, there are still measures of the extent of motion. These 

 measures are firstly the points of highest elevation and greatest 

 depression — secondly, the corresponding intervals of time — 

 thirdly, the perception of the rush in progressing through the 

 atmosphere, for not only does the cessation of the rush indicate 

 the points of greatest elevation, but its increase or diminution, 

 indicates continuously all other points. Hearing ,naaj also be 

 mentioned, as it contributes to the conviction of the mind as to 



