In scientific work the main thing just now about which I am engaged is a revision of the Dinosauria, with an eye to the “Descendenz Theorie.”  The road from Reptiles to Birds is by way of Dinosauria to the Ratitae.  The bird “phylum” was struthious, and wings grew out of rudimentary forelimbs.

You see that among other things I have been reading Ernst Haeckel’s “Morphologie.”

[The next two letters reflect his views on the proper work to be undertaken by men of unusual scientific capacity:—­]

Jermyn Street, January 15, 1868.

My dear Dohrn,

Though the most procrastinating correspondent in existence when a letter does not absolutely require an answer, I am tolerably well-behaved when something needs to be said or done immediately.  And as that appears to me to be the case with your letter of the 13th which has this moment reached me, I lose no time in replying to it.

The Calcutta appointment has been in my hands as well as Turner’s, and I have made two or three efforts, all of which unfortunately have proved unsuccessful to find:  (1) A man who will do for it and at the same time (2) for whom it will do.  Now you fulfil the first condition admirably, but as to the second I have very great doubts.

In the first place the climate of Calcutta is not particularly good for anyone who has a tendency to dysentery, and I doubt very much if you would stand it for six months.

Secondly, we have a proverb that it is not wise to use razors to cut blocks.

The business of the man who is appointed to that museum will be to get it into order.  If he does his duty he will give his time and attention to museum work pure and simple, and I don’t think that (especially in an Indian climate), he has much energy left for anything else after the day’s work is done.  Naming and arranging specimens is a most admirable and useful employment, but when you have done it is “cutting blocks,” and you, my friend, are a most indubitable razor, and I do not wish to have your edge blunted in that fashion.

If it were necessary for you to win your own bread, one’s advice might be modified.  Under such circumstances one must do things which are not entirely desirable.  But for you who are your own master and have a career before you, to bind yourself down to work six hours a day at things you do not care about and which others could do just as well, while you are neglecting the things which you do care for, and which others could not do so well, would, I think, be amazingly unwise.

Liberavi animam! don’t tell my Indian friends I have dissuaded you, but on my conscience I could give you no other advice.

We have to thank you three times over.  In the first place for a portrait which has taken its place among those of our other friends; secondly for the great pleasure you gave my little daughter Jessie, by the books you so kindly sent; and thirdly, for Fanny Lewald’s autobiography which arrived a few days ago.