I thank you for your very interesting letter, which it has given me much pleasure to receive. I never heard of anything so odd as the Prior in the Holy Catholic Church believing in our ape-like progenitors. I much hope that the Jesuits will not dislodge him.
What a wonderfully active man you are! and I rejoice that you have been so successful in your work on sponges. (248/1. "Die Kalkschwamme: eine Monographie; 3 volumes: Berlin, 1872. H.J. Clark published a paper "On the Spongiae Ciliatae as Infusoria flagellata" in the "Mem. Boston Nat. Hist. Soc." Volume I., Part iii., 1866. See Hackel, op. cit., Volume I., page 24.) Your book with sixty plates will be magnificent. I shall be glad to learn what you think of Clark's view of sponges being flagellate infusorians; some observers in this country believe in him. I am glad you are going fully to consider inheritance, which is an all-important subject for us. I do not know whether you have ever read my chapter on pangenesis. My ideas have been almost universally despised, and I suppose that I was foolish to publish them; yet I must still think that there is some truth in them. Anyhow, they have aided me much in making me clearly understand the facts of inheritance.
I have had bad health this last summer, and during two months was able to do nothing; but I have now almost finished a next edition of the "Origin," which Victor Carus is translating. (248/2. See "Life and Letters," III., page 49.) There is not much new in it, except one chapter in which I have answered, I hope satisfactorily, Mr. Mivart's supposed difficulty on the incipient development of useful structures. I have also given my reasons for quite disbelieving in great and sudden modifications. I am preparing an essay on expression in man and the lower animals. It has little importance, but has interested me. I doubt whether my strength will last for much more serious work. I hope, however, to publish next summer the results of my long-continued experiments on the wonderful advantages derived from crossing. I shall continue to work as long as I can, but it does not much signify when I stop, as there are so many good men fully as capable, perhaps more capable, than myself of carrying on our work; and of these you rank as the first.
With cordial good wishes for your success in all your work and for your happiness.
LETTER 249. TO E. RAY LANKESTER. Down, April 15th .
Very many thanks for your kind consideration. The correspondence was in the "Athenaeum." I got some mathematician to make the calculation, and he blundered and caused me much shame. I send scrap of proofs from last edition of the "Origin," with the calculation corrected. What grand work you did at Naples! I can clearly see that you will some day become our first star in Natural History.
(249/1. Here follows the extract from the "Origin," sixth edition, page 51: "The elephant is reckoned the slowest breeder of all known animals, and I have taken some pains to estimate its probable minimum rate of natural increase. It will be safest to assume that it begins breeding when thirty years old, and goes on breeding till ninety years old, bringing forth six young in the interval, and surviving till one hundred years old; if this be so, after a period of from 740 to 750 years, there would be nearly nineteen million elephants alive, descended from the first pair." In the fifth edition, page 75, the passage runs: "If this be so, at the end of the fifth century, there would be alive fifteen million elephants, descended from the first pair" (see "Athenaeum," June 5, July 3, 17, 24, 1869).)
LETTER 250. TO C. LYELL. Down, May 10th .