BiblioVault may have an electronic file which would meet your requirements for this title:
Island Life: Or, the Phenomena and Causes of Insular Faunas and Floras, Including a Revision and Attempted Solution of the Problem of Geological Climates
Alfred Russel Wallace, David Quammen and Lawrence R. Heaney
Paper: 978-0-226-04503-0
Electronic: 978-0-226-04517-7