Charles Lyell has asked WE to pass his opinions on the MS of Origin to CD via Murray. WE is convinced of the value of CD’s researches but "to put forth the theory without the evidence", as in the MS, "would do grievous injustice to his views". The omission of these facts reduces both the philosophical and popular value of the work, by virtue of its dryness.

Supports Charles Lyell’s suggestion that CD should first publish his observations on pigeons with a theoretical outline, for "[e]very body is interested in pigeons". Such a work would generate wider interest and be better understood. A subsequent, larger book would then be approached with impartiality "not to say favour" by a wider public.