To Wilhelm Breitenbach   13 February 1880

Dear Sir.

I thank you sincerely for your kind & courteous letter of the 10^th.¹ I hope that you will be so good as to return to the Society of Students at Jena my cordial acknowledgments of their kind congratulations on my birthday—² I wish them every kind of success in their studies & throughout life— He who heartily sympathises with the work done by other men shows that he works for the sake of discovering the truth & not for gaining distinction; & this is the best of all auguries for success in the pursuit of Science.

Believe me, My dear Sir. | Yours very faithfully. | Charles Darwin.