Dear Sir

I hope that you will excuse the liberty which I take in suggesting a small modification in one of your interesting trials on the formation of diamonds.¹

It is simply to use the flesh of an animal, mixed perhaps with some vegetable matter, to give you the necessary carbon in conjunction with nitrogen; & such perhaps has been the source of the carbon for diamonds in their natural place. I make the suggestion solely on the supposition that it would not necessarily interfere with your main object. For several years I have much wished that some one w^d observe what chemical products (if any) w^d result from the slow cooling of all the various elements which are present in every living organism, after they had been subjected to intense heat & pressure. I have imagined that possibly something of the nature of a protein compound might be generated, as all the necessary elements, phosphorus, sulphur, potash &c &c w^d be present. In my own experiments on living plants, I am very fond of trying what I call “a fool’s experiment”; & such experiments, tho’ rarely successful in a direct manner, have often led to interesting side-results.

Pray do not trouble yourself to answer this letter, & excuse me if my suggestion is impracticable, or appears to you to be too much of a fool’s experiment—

Dear Sir | yours faithfully | Charles Darwin