My dear Jenyns

I must thank you for your very kind note forwarded to me from Down.—¹ I have been much out of health this summer & have been hydropathising here, for last six weeks with very little good as yet.— I shall stay here for another fortnight at least.

Please remember that my Book is only an abstract & very much condensed & to be at all intelligible must be carefully read. I shall be very grateful for any criticisms. But I know perfectly well that you will not at all agree with the lengths which I go.² It took long years to convert me.— I may of course be egregiously wrong; but I cannot persuade myself that a theory which explains (as I think it certainly does) several large classes of facts, can be wholly wrong; notwithstanding the several difficulties which have to be surmounted somehow, & which stagger me even to this day.

I wish that my health had allowed me to publish in extenso; if I ever get strong enough I will do so, as the greater part is written out, & of which M.S. the present volume is an abstract.—

I fear this note will be almost illegible; but I am poorly & can hardly sit up.

Farewell with thanks for your kind note & pleasant remembrances of good old days | Yours very sincerely | C. Darwin