One of the real pleasures afforded in reading Charles Darwin’s correspondence is the discovery of areas of research on which he never published, but which interested him deeply. We can gain many insights about Darwin’s research methods by following these ‘letter trails’ and observing how correspondence served as a vital research tool for him.
Darwinian evolution theory fundamentally changed the way we understand the environment and even led to the coining of the word 'ecology'. Darwin was fascinated by bees: he devised experiments to study the comb-building technique of honey bees and used his children to observe the flight paths of bumblebees around their home.
One of the most fascinating aspects of Charles Darwin’s correspondence is the extent to which the experiments he performed at his home in Down, in the English county of Kent, seem to prefigure modern scientific work in ecology.
A confounded cock ground the crimson seeds up so CD could not find them in its excrement. CD is puzzled by how seeds can be disseminated if merely ground up by birds. Perhaps like acorns from seeds accidentally dropped by birds?
A woodcock’s leg with dry clay clinging to it, from which CD has grown a microscopical rush.
Spencer would have been wonderful if he had trained himself to observe more.
On New Zealand flora and connection with Australia.
Difficulty of speculating about the amount of organic chemical change at different periods.
Thanks CD for sending F. H. G. Hildebrand’s book on fertilisation [Die Geschlechter-Vertheilung bei den Pflanzen(1867)]
and J. D. Hooker’s "Lecture on insular floras".
Describes work on Rubiaceae,Oxalis,
and on crossing orchids. Lists crosses made.
As for CD’s query concerning sexual differences among invertebrates, he gives the case of the local amphipod,Brachyscellus diversilor. Male differs in shape of antennae and coloration.
Also mentions local fish in sea near Sta Catharina which emits melodic tone to attract females.
CD is much interested in FB’s remarks inLand and Wateron the apparent excess of male trout over females and asks for further information on other fish, birds, and domestic quadrupeds.
LA clarifies his opposition to CD’s views, which does not blind him to the great value of CD’s original researches.
Answers CD’s questions regarding sexual coloration of Amazonian fishes and the protuberances on the head of maleGeophagusandCichladuring the spawning season [seeDescent, pp. 520, 529].
Thinks GHL’s articles are quite excellent; hopes they will be republished.
Discusses adaptation. Doubts whether similar conditions without selection can produce similar organs independent of blood relationship: "resemblances due to descent and adaptation can commonly be distinguished".
Discusses luminous insects, electrical organs of fish, thorns and spines.
