On the "doubtful & obscure" subject of marriage of cousins, CD believes, that judging from the analogy of animals, no direct evil would follow from their marriage. He would, however, expect the offspring of unrelated parents to be somewhat superior in size and vigour. The injury from the increase of any bad tendency common to the family seems to CD more to be feared than mere consanguinity; "the good effects of crossing distinct families I look at as great & undoubted".

Requests EF’s vote and support in favour of Henry Parker for membership in the Athenaeum.

Finding that the leaves of Drosera digest all the phosphate of lime out of bones and then remain clasped over the bones for a long time, CD wants to determine whether it is the phosphate of lime or the animal matter in the bones that keeps them clasped. He asks EF to send 2 or 3 grams of pure phosphate of lime for his testing. [See 9411.] Will experiment in the summer using EF’s suggestion that leaves might serve to test weak sewage. Results of Sanderson’s experiments with acids of great use.

Thanks for the pure phosphate of lime.

Requests permission to call briefly to discuss Drosera.

Thanks for letter relating to domesticated bullfinches’ instinctively cutting off cowslips [see 9430]. Suggests observing whether the birds swallow any part of flower or particular parts.

Requests sewage water (and oleic acid) for experiments to determine sensitivity of leaves [of Drosera].

Thanks for the sewage water and the oleic acid. The former does not seem to act.

Asks for the specific gravity of common phosphate of ammonia.

Utricularia catch freshwater Crustaceans, which cannot be digested and rot in the bladders. CD is interested to identify any substance produced in the putrefaction before it is resolved into gases and salts of ammonia. He has reason to believe that the plant absorbs such products.

Acknowledges the information about the phosphate and about putrefaction. Regrets that there is no knowledge of the conjectured substance. [See 9671.]