BOOKS, 



3* 



little formula'. One of the saddest things about 

 the excitement was the contempt of the opi- 

 nions of some of the wisest and most scienti- 

 fic men of the time, such as Quatrefages and 

 Owen, who gave to the craze its true name of 

 " Conjectural biology." The idea even among 

 those who ought to know better,that we "didn't 

 know everything down in Judee," or anywhere I 

 else, about the evolution of life before Darwin's 

 time is a pure illusion. 



Darwin, as the result of experiments made 

 by him on the fertilisation of flowers, drew 

 several conclusions. We select two as good 

 examples of the weakness of the Darwin case. 



" The first and most important ... is 

 that, generally, cross-fertilisation is beneficial 

 and self- fertilisation often injurious. " And, 

 again: " Scarcely any result from my experi- 

 ments has surprised me so much as this of the 

 prepotency of pollen from a distinct individual 

 over each plant's own pollen, as proved by the 

 greater constitutional vigour of crossed seed- 

 lings." Furthermore: "The simple fact of the 

 necessity in many cases of extraneous help for 

 the transport of pollen renders it highly pro- 

 bable that some great benefit is gained ; and 

 this conclusion has now been firmly established 

 by the proved superiority in growth, vigour, 

 and fertility of crossed parentage over those of 

 self-fertilised parentage." 



By self-fertilisation is meant that the pollen 

 of its own flower (or of a flower on this same 

 root) fertilises its own stigma. By cross-fertili- 

 sation is meant that pollen from a flower grow- 

 ing on a different root (in case of heterostyled 

 plants one of a different form) was applied to the 

 stigma. Darwin, in making his experiments, 

 made use of the following plan, as described by 

 himself: "A single plant, if it produced a suffi- 

 ciency of flowers, or two or three plants, were 

 placed under a net stretched on a frame. On 

 the plants thus protected" (from the visits of 

 bees and other insects) "several flowers were 

 marked, and were fertilised with their own 

 pollen, and an equal number on the same plants 

 were at the same time crossed with pollen from 

 a distinct plant. The crossed plants had not 

 their anthers removed." 



The author points out the weak points in 

 Darwin's method as follows : — 



" The cross-fertilised plants had a great 

 advantage. The self-fertilised plants had only 



their own pollen, and that developed under a 

 net to fertilise them ; but the cross-fertilised 

 plants had not only their own pollen — their 

 anthers were not removed — but pollen from 

 another plant applied to them as well, and that, 

 too, grown naturally outside the net; for Darwin 

 wished, by leaving the flowers their own pollen, 

 and, at thesame time, crossing them with other 

 pollen,' to make the experiments as like as pos- 

 sible to what occurs under Nature, with plants 

 fertilised by the aid of insects. 'The cross-ferti- 

 lised had, consequently, two sets of pollen to 

 choose between, and whichever happened to be 

 most in its prime, that would exercise a 'pre- 

 potent' influence in the fertilisation. But the 

 flowers fertilised with their own pollen had no 

 other pollen but their own to depend upon, and 

 that developed under a net, which must fertilise 

 them or none at all." 



" Such a system of experiments evidently 

 gave to the cross-Jerti/ised flowers a very great 

 advantage over the self-fertilised ones,and con- 

 sequently a very great advantage for the pro- 

 duction of better developed seeds, and for the 

 stronger growth and vigour of the seedlings 

 raised from them" (quoted from p. 60). 



Darwin's experiments, which he said 

 proved the " prepotency of pollen from another 

 plant over that of a plant's own pollen," merely 

 proved the prepotency of pollen grown on a 

 plant uncovered over that of pollen grown 

 under the shade of a "close-meshed net." The 

 wonder is that Darwin failed to perceive the 

 unequal conditions. Now that his method is 

 explained his errors will be patent to every 

 florist. They will thus be saved from unneces- 

 sary and unprofitable outlay which many in 

 the past have suffered, from placing reliance 

 on Darwin's views ; as the agriculturists in New 

 Zealand and Australia about the Red Clover, 

 and many in our public and private gardens 

 and nurseries about cross-fertilisation. 



In many cases also the flowers under the 

 net were left to pollinate themselves, and the 

 exclusion of the full influence of the wind was 

 a further disadvantage even to the efficient 

 pollination of the self-fertilised flowers. 



"The influence of the solar rays, too,would 

 be greatly diminished in passing through a 

 closely -meshed net, and consequently they 

 would be much debarred from exercising their 

 full maturing power on the anthers, and so on 



