Congratulates CD on testimonials from the savants of Germany and the Netherlands [Nature 15 (1877): 356, 410–12] and generally on his contributions to biology.

Asks if and when CD’s "Variability of organic beings in a state of nature", as projected in 1868 [see Variation 1: 4] is to appear.

CD doubts that he will be able to do much more that is new, but cannot bear idleness. Has great amount of material on variation under nature, but so much has been published since the appearance of the Origin that he doubts he has the power of mind to render the mass into a digested whole.