[[p. 63]] Rosehill, Dorking,
Oct. 7th, 1877.

     My dear Sir,--I have read the passages you marked, as well as a good many other parts of your book, with [[p. 64]] much pleasure. I was particularly pleased with your suggestion (which had not occurred to me) that fruits, in our sense of the word, are much more recent developments than flowers, because they attract chiefly mammals and birds instead of insects.

     There is, I admit, a partial contradiction between the view that 'red' excites animals on account of its glaring contrast, and that yet the perception of it by man is recent. The latter view must, I believe, be incorrect, and should be stated, I think, even more hypothetically than I have put it. I have just been reading Mr. Gladstone's interesting paper, which is almost wholly on Homer's colour terms, or rather the absence of them. The evidence is most curious, but I think it only goes to show that language was imperfect, and that 'colour' was too infinitely varied and of too little importance to early man to have received a systematic nomenclature. 'Flowers' and 'birds' and 'insects' were despised, and the colours of more important objects, as the 'sea,' 'sky,' 'earth,' 'iron,' 'brass,' etc., were not only not pure colours (generally), but subject to endless fluctuations.

     Your remarks on 'nuts' are very good. I quite overlooked that case, and shall refer to you when I reprint my paper with others in a volume shortly.

     I think that all the coloured fruits which are poisonous to 'man' are eatable to some birds, etc. They are far too numerous to be accounted for otherwise. --With many thanks, believe me, yours faithfully,

Alfred R. Wallace.

[[p. 72]] Waldron Edge, Duppers Hill,
Croydon, Feb. 17th, 1879.

     Dear Sir,--Very many thanks for your book on 'The Colour Sense.' I have just finished reading it through, and I have seldom read a book with more pleasure. It is full of original and suggestive matter, and is admirable in its clearness and the thorough manner in which many aspects of the subject are discussed.

     Of course, I totally dissent from your adoption of 'sexual selection' as a 'vera causa,' though of course you are quite justified in following Darwin rather than me as an authority. I think you overstrain many parts of your argument, [[p. 73]] especially the connection of bright colours in animals with the colours of the food. I also think you lay far too great stress on our knowledge of the first appearance of certain groups of plants and insects; but I shall probably deal with these questions in a notice I may write of your book.

     I must say I do not see the least force in what you say as to the probable 'identity' of colour sense in 'ourselves' and 'insects.' For it is clear that the optical organs of these two have been developed 'separately'; and if the sensations were 'alike,' it would be a 'coincidence' which we have no reason to expect. The fact that insects differentiate most of the contrasted colours by no means proves, or even affords any probability, that their 'sensations' are anything 'like' ours, and I still maintain that the probability is they are 'unlike.' With 'birds' and ourselves, on the contrary, we may be almost sure the sensations are similar, because our eyes and nervous systems are derived probably from a common ancestor who had both well fairly developed.

     A day or two ago, I received from a gentleman residing in Germany a very clever article on the 'Origin of the Colour Sense,' in which he shows physiological grounds for the belief in the great inferiority of the colour sense in all mammals, and the inferiority even of ourselves to birds.

     I am very sorry you did not put a good index to your book. It is most difficult to find any special point you want, and causes endless trouble. I feel so strongly on this that I think the publication of Indexless books should be 'felony' without benefit of Clergy! [Compare with this mild penalty that suggested--was it not by Carlyle?--to send the felon who makes no index to his book a couple [[p. 74]] of miles the other side of hell, where the devil can't reach him for the stinging nettles. --E. C.]

     I need not wish your book success, for it is sure to be successful, as it well deserves to be.--Yours very faithfully,

Alfred R. Wallace.

     P.S.--In my original paper in 'Macmillan's Magazine' [September 1877], I spoke doubtfully about the prehistoric want of colour sense, because the subject came upon me suddenly just as I had finished my paper. I still think, however, that 'colour blindness' is an indication of imperfection, and I hope evidence will soon be obtained as to its equal prevalence or absence in some semi-civilised race. I doubt its being a product of civilisation, since civilised man makes more use of colour than savage man. It is an interesting and important question. --A. R. W.