Paper, 'On the structure of the crystalline lens in fishes and quadrupeds, as ascertained by its action on polarised light' by David Brewster in a letter to the Rt Hon Sir Joseph Banks Illustrations for this paper have been separated from the manuscript and are found at PT/73/5/13. Subject: Zoology / Physics Published in Philosophical Transactions as 'On the structure of the crystalline lens in fishes and quadrupeds, as ascertained by its action on polarised light. By David Brewster, LL. D. F. R. S. Lond. and Edin. In a Letter addressed to the Right Hon. Sir Joseph Banks, Bart. G. C. B. P. R. S'. Written by Brewster in Edinburgh. Read 20 June 1816. Abstract published in Abstracts of the Papers Printed in the Philosophical Transactions of the Royal Society of London [later Proceedings of the Royal Society of London], Volume 2, 1833. 20 May 1816