Suggests that the scarcity of holly berries is owing to the scarcity of bees during the spring, rather than to frost. He does not know what caused the scarcity of bees.

CD confesses his error with respect to the cause of the scarcity of holly berries. It appears that several causes in combination have led to it. CD still believes rarity of bees played a part, though a subordinate one.

Replies to some of George Henslow’s criticisms [of Cross and self-fertilisation] made in his article ["Fertilisation of plants", Gard. Chron. n.s. 7 (1877): 203–4].

Reports on the effect of potato blight in his crop.

Solicits information about the kind of syphon required to convey water from a proposed large water tank to existing smaller ones.

CD describes his experiments on the effects on germination of the immersion of seeds in sea-water. Hopes to throw light on the distribution of plants. Asks readers of Gardeners’ Chronicle to inform him whether such experiments have already been tried and what class or species of seeds they suppose would be particularly liable to be killed by sea-water.

Reports on his experiments on action of sea-water on seeds and the bearing of his investigations on the theory of centres of creation and Edward Forbes’s theory of continental extensions to account for distribution of organic forms. CD’s experiments confirm germination powers were retained after 42 days’ immersion by seven out of eight kinds of seeds.

Reports a case of charlock seeds that retained their vitality for at least eight or nine years. He suggests that their power of retaining vitality when buried in damp soil may be an element in preserving the species and therefore seeds may be specially endowed with this capacity, while the power of retaining vitality in dry, artificial conditions may be an indirect accidental quality of little or no use to the species.

Sends final results of his experiments on the vitality of various kinds of seeds immersed in sea-water. Corrects a false assumption he made in an earlier letter [1684] that plants with ripe seeds would float for some weeks. Now finds that they sink within a month. Since all the seeds he tried sank in sea-water, his experiments are of little or no use "in regard to the distribution of plants by drifting of their seeds across the sea".

Describes his experiments with kidney beans to test the agency of bees in their fertilisation. His results suggest they are essential.

Asks what George Swayne could mean by the advantage of artificial fertilisation of early beans [Trans. Hortic. Soc. Lond. 5 (1824): 208–13].

Has observed that hive-bees, which normally suck nectar from the flower of the kidney bean, will use holes cut through the calyx by humble-bees, though the holes cannot be seen from the mouth of the flower. Suggests hive-bees see humble-bees at work and understand what they are doing and "rationally" take advantage of the shorter path to the nectar. [See also 2359.]

Hopes readers will send information on the permanence of cross-bred plants and animals. No one doubts that cross-bred productions tend to revert in various degrees to either parent for many generations. But are there not cases of crossed breeds of sheep and pigs that breed true? CD believes occasional cross-breeding of varieties is advantageous in nature as well as under domestication. [See reply to this letter by J. O. Westwood, Gard. Chron. (1860): 122.]

CD acknowledges that Patrick Matthew, in his appendix to Naval timber and arboriculture (1831), anticipated by many years CD’s explanation of the origin of species by natural selection. CD was ignorant of the work. If another edition of Origin is called for, CD will insert a notice to the foregoing effect.

Wants to hear from readers about the way in which the bee-orchid (Ophrys apifera) is fertilised. He has always found it to be self-fertilised but greatly doubts that the flowers of any plant are fertilised for generations by their own pollen. The bee-orchid has sticky glands, which would make it adapted for fertilisation by insects; this makes him want to hear what happens to its pollen-masses in places he has not observed.

Asks for any published reference providing account of the movement of the viscid hairs or leaves of Drosera lunata, an Indian Drosera which Lindley cites in Vegetable kingdom, p. 433.

Asks M. J. Berkeley to identify the microscopical spherical bodies CD found in drops of yellowish rain-water that fell on his garden in a brief shower.

Requests information on published observations on the proportional number of males and females born to various domestic animals.

Reports detailed observations on humble-bees boring holes in flowers to extract nectar instead of brushing over the stamens and pistils. Some hive-bees seem to use the holes made by the humble-bees; speculates that this would be a case of acquired knowledge in insects.

Is interested to know whether there are differences in the period of development of horns in sheep in those breeds in which horns are common to both sexes, and in those in which horns are confined to males.

In response to a query from a Mr D. T. Fish, CD reaffirms his view of the efficiency of worms in bringing up in their intestines fine soil from below the surface. Reports on observations, during the past 25 years, which confirm his views.

Sends some examples of Gentiana that he thinks may shed light on the origin of double flowers. Since specimens grew in sterile soil their double flowering cannot be attributed to excess food. CD advances the hypothesis that some change in natural conditions causes sterility, which then causes compensatory development of petals, the organs closest in morphology to those whose functions have been checked.