Before inner ear fluids and their role in balance were understood, what other theories did people have about the dizziness brought on by spinning rapidly?
Vestibular specialist here! It has been a little tough to answer this question since I don’t know a lot about the history of vestibular research in XIX’ century, but I have a piece of answer which comes from this book (notice that one half of the pages are in German and another half are the English translation).
This book is a translation of Ernst Mach’s work which was published in 1875. In this work, he is actually explaining and understanding how the inner ear fluids work and why dizziness occurs when spinning rapidly. So this work is not directly relevant to your question. However, he mentions a couple of explanations that were proposed previously by Purkinje and Breuer (pp 79-83).
To summarize: both authors observed the vestibulo-ocular reflex, i.e. the eyes rotating in a direction opposite to the head so as to stabilize gaze. They also observed that these eye movements cease when the rotation lasts for too long and that this leads to the sensation of vertigo while rotating. Purkinje suggests that this is due to muscle fatigue (so this was one explanation). Breuer doesn’t really explain why it is so, but he observes that eye movements resume after the rotation stops and that it leads to post-rotatory dizziness.
That’s all I can find on the topic ! I don’t have any XIX’ century literature, except for this book.
Thanks for that reply, it is informative.
Anyone know of references going back even further?
Here is another piece of information… not of huge value but it is still something. In the chapter “swinging” of this book written in 1804, a psychiatrist (if one may call him so) describes how to use a swinging chair to treat psychiatric disorders.
Although he discusses the effects of swinging for several pages, he never alludes to any theory about why it induces dizziness. In p. 143, he states:
That seems to suggest that people didn’t have any definite theory about where dizziness came from in 1804.
Theophrastus, who (as I hope you know) was Aristotle’s student and collaborator, and who succeeded him as head of the Lyceum. wrote a whole book on dizziness. Here you go.
Unless Aristotle himself, or Plato, had something significant to say about the subject, I do not think you are going to find anything much that is older.