ERASMUS DARWIN. 263 



He believes it to be shown by the existence of rudimentary or 

 useless parts, such as the nipples of male animals, or the useless toes of 

 swine, that animals have undergone changes — that monsters prove the 

 same thing, but that in some cases monstrosities may be progressive 

 rather than retrogressive, and aim at something to come. Species are 

 not permanent, but may be transmuted — the tendency being an 

 increasing perfection. Animals are first aquatic, then amphibious, and 

 finally aerial ; and this is more or less seen in embryology. With respect 

 to the Origin of Species in plants, he quotes Linnaeus's opinion that at first 

 there were only as many species as there are tnie natural orders. He 

 discusses the theory of man's quadrumanous descent. 



He gives due influence to a Struggle for Existence as regards the 

 extinction and modification or improvement of animals. "With respect 

 to Sexual Selection, he obsei^es "the final cause of this contention 

 amongst the males seems to be that the strongest and most active 

 animal should propagate the species, which should hence become 

 improved." He lays stress on the effect of the natural or artificial 

 cultivation of animals, hence the changes brought about in the horse, 

 dog, sheep, rabbit, and pigeon. He also attributes an influence towards 

 the gi-adual production of species to the nisus to obtain food and ensure 

 security. This last is rather Lamarckian than Darwinian, and it may 

 perhaps be seen that even in respect to the eft'ects of cultivation and 

 sexual selection we have not lucidly expressed the saHent point of the 

 modem hj'pothesis — the certain but gradual effect in the production 

 of species of shght, favourable variation, when developed by Natural 

 Selection, rendered sufficiently efficient by length of time and unhmited 

 numbers of the individuals. The elder philosopher does not teU us that 

 the changes are so inevitable and undii-ected. He saw in the colouration 

 of birds and their eggs, in the habits of insects, and in the modes of 

 vegetable fertilisation, &c., as weU as in physical nature in general, signs 

 of design or extraneous intelligence. Nature, he says, is subject " to 

 immutable laws impressed on matter by the Great Cause of Causes, 

 Parent of Parents, Ens Entium." He is more generally correct in 

 attributing some modification of species to climate and season, than to 

 hybridity, which appears to have, on the whole, the reverse effect. 



He seems to have taken an interest in the modes of fertihsation of 

 flowers, but was thoroughly ignorant of the participation of insects in 

 that act. The corolla for him was a thing of beauty, and also for the 

 respu-ation of the sexual organs ; the nectar nourished the seeds, and 

 ■was curiously guarded from the injurious depredation of insects, a 

 superabundance of it only being, in a few instances, as in Cacalia 

 suaveolens, acceded to them. He noticed the curious mechanism of the 

 flowers of the broom, but did not discover that this mechanism is 

 generally brought into play by the visits of bees. He gives curious 

 examples of contrivances to effect ordinary fertilisation, mentions the 

 ripening of different sets of anthers at different times, and the different 

 length of sets of stamens in the same species, in Lythrum and Lychnis 

 for instance ; as well as the great appetency of the stigma in some 

 flowers, as Collinsonia, for foreign poUen, which he calls vegetable 



