To James Brown Gibson   [after 29 June 1862]¹

Sir

I hope that you will permit me to return to you my sincere & cordial thanks for the kind manner with which you have acceded to my wishes in the endeavour the endeavour to find out whether there exists any re— [between] complexion & liability & tropical diseases.—² Without your aid nothing whatever could have been done.—

The result may not [illeg] turn out a complete failure; but I have not ventured to make my request without [mature] consideration.—

With my sincere thanks for all your kindness   I [hope] to remain | Your oblig Servt, | C. Darwin