Sea-sickness, its true cause and cure / by H. Norman Barnett.

  • Barnett, H. Norman (Henry Norman), 1872-
Date:
1907
Catalogue details

Licence: In copyright

Credit: Sea-sickness, its true cause and cure / by H. Norman Barnett. Source: Wellcome Collection.

    22/48 page 18
    Physiology of Semicircular Canals These canals have two functions : (1) that directly con- nected writh hearing, by collecting in their fluid contents sonorous undulations from the bones of the cranium; (2) that indirectly connected with the sense of hearing, by informing us as to our equilibrium, by means of the constant alterations in pressure of the fluid within the canals. This is closely associated with co-ordination of muscular movements. It has been found that when the horizontal canal is divided in a pigeon a constant move- ment of the head from side to side occurs. When one of the vertical canals is divided, up-and-down move- ments are produced. These movements are associated with loss of co-ordination, as after the experiment the bird is unable to fly in a proper manner. Having regard to these anatomical and physiological facts, and in view of the proofs derived from observa- tion of the signs and symptoms of sea-sickness, there > can be little doubt— 1. That the true cause of sea-sickness is irritation of the terminal fibres of the auditory nerve distributed to the membrane of the semi-circular canals. 2. That the irritation is conveyed, through the nerve connexions mentioned above, to the vagus, and possibly to the sympathetic, and thence to the walls of the stomach. 8. That it is primarily an irritation of cranial nerves. 4. That this irritation is caused by the motion of a ship on rough water, but not by this alone. Any motion which is contrary to that usually experienced by the fluid contained in the semicircular canals will
    digitised image 1
    digitised image 2
    digitised image 3