My admiration for the man only grows with time. Here's an excerpt from a post on LiveScience:
Darwin's correspondence to friends, family, and colleagues reveals he held very skeptical views about psychics, the paranormal, and alternative medicine. For example, in a Sept. 4, 1850, letter to his second cousin Rev. William Darwin Fox, Darwin was scathingly dismissive of psychic powers (clairvoyance) and homeopathy:
"You speak about Homeopathy; which is a subject which makes me more wrath, even than does Clairvoyance: clairvoyance so transcends belief, that one’s ordinary faculties are put out of question, but in Homeopathy common sense & common observation come into play, and both these must go to the Dogs, if the infinetesimal doses have any effect whatever." (Here Darwin is referring to the illogical homeopathic premise that tiny amounts of a drug are more effective than larger doses.)
Darwin then notes that in order for homeopathy to be scientifically tested, it would need to be studied against a control group: "How true is a remark I saw the other day...in respect to evidence of curative processes, viz that no one knows in disease what is the simple result of nothing being done, as a standard with which to compare Homeopathy & all other such things. It is a sad flaw, I cannot but think in my beloved Dr. Gully, that he believes in everything..."