Sir--A correspondent signing himself "A. M." in the issue of February 21st says: --"Will the writer (of an article on barrel-organs) refer to anything bearing upon natural selection and the struggle for existence in Dr. Darwin's work?" This is one of the trade forms by which writers imply that there is no such passage, and yet leave a loophole if they are proved wrong. I will, however, furnish him with a passage from the notes of Darwin's Botanic Garden:-

"I am acquainted with a philosopher who, contemplating this subject, thinks it not impossible that the first insects were anthers or stigmas of flowers, which had by some means loosed themselves from their parent plant; and that many insects have gradually in long process of time been formed from these, some acquiring wings, others fins, and others claws, from their ceaseless efforts to procure their food or to secure themselves from injury. The anthers or stigmas are therefore separate beings."

This passage contains the germ of Mr. Charles Darwin's theory of the origin of species by natural selection:-

"Analogy would lead me to the belief that all animals and plants have descended from one prototype."

Here are a few specimens, his illustrations of the theory:-

"There seems to me no great difficulty in believing that natural selection has actually converted a swim-bladder into a lung or organ used exclusively for respiration." "A swim-bladder has apparently been converted into an air-breathing lung." "We must be cautious in concluding that a bat could not have been formed by natural selection from an animal which at first could only glide through the air." "I can see no insuperable difficulty in further believing it possible that the membrane-connected fingers and forearm of the galeopithecus might be greatly lengthened by natural selection, and this, as far as the organs of flight are concerned, would convert it into a bat." "The framework of bones being the same in the hand of a man, wing of a bat, fin of a porpoise, and leg of a horse, the same number of vertebrae forming the neck of the giraffe and of the elephant, and innumerable other such facts, at once explain themselves on the theory of descent with slow and slight successive modifications."

I do not mean to go through your correspondent's letter, otherwise "I could hardly reprehend in sufficiently strong terms" (and all that sort of thing) the perversion of what I said about Giordano Bruno. But "ex uno disce omnes"--I am, etc.,

DARWIN ON SPECIES: [From the Press, 18 March, 1863.]