by which in the natural course of things the pollen finds its way from the anthers to the stigmas. He ascribed perhaps too much to the agency of the wind and the oscillations of the flower from any cause; at the same time he was the first who recognised the great importance of the insect-world to pollination in flowers. 'In flowers,' he says, 'in which pollination is not produced by immediate contact in the ordinary way, insects are as a rule the agents employed to effect it,' (later observation has shown that they are generally so employed even in cases where actual contact is possible), 'and consequently to bring about fertilisation also; and it is probable that they render this important service if not to the majority of plants at least to a very large part of them, for all the flowers of which we are speaking have something in them which is agreeable to insects, and it is not easy to find one such flower, which has not a number of these creatures busy about it.' He noticed the dichogamous construction in Epilobium, but did not further pursue his observation. He next examined the substance in flowers which is agreeable to insects; he collected the nectar of many flowers in considerable quantities, and found that it gave after evaporation of the water a kind of sweet-tasted honey; this honey was unpalatable only in Fritillaria imperialis, which is avoided by the humble-bees. He had no doubt therefore, that bees procure their honey from the nectar of flowers. How greatly he was interested in the relations between the existence of certain plants and that of certain animals, relations which were neglected till Darwin once more brought them into notice in quite recent times, is shown by his investigation into the propagation of the mistletoe (1763); he calls special attention to the fact, that not only must the pollination of this plant be effected by insects, but that the dissemination of its seeds is also exclusively the work of birds, and that the existence of the plant therefore is dependent on two different classes of living creatures.
