THE PER TILISA TION OF FL WERS. 339 



humblebees in turn are killed by field-mice, whilst cats extirpate tha 

 rodents. As old maids conserve the feline race, it is alleged that 

 the continuance of the British intellect is dependent upon such 

 conservation so that a scientific justification of spinsterhood is thus 

 rendered possible. 



Sprengel laid down the axiom, already mentioned, that " Nature 

 does not wish any complete flower to be self-fertilised." Darwin in, 

 turn improves upon this dictum in his assertion that " Nature 

 abhors perpetual self-fertilisation." That "cross-fertilisation is 

 generally beneficial, and self- fertilisation injurious," is thus a stable 

 result of botanical investigation. This result may not enable us 

 fully to comprehend that "law within the law" which regulates the 

 well-being of the plant-world ; but it may at least lead us plainly 

 enough to a nearer fact of life namely, that there exists in nature 

 an innate tendency to variation and change, and that by furthering 

 the fullest possible development of seeds, as well as by the cross- 

 fertilising of plants, there is being illustrated that tendency to evolve 

 new varieties and species on the existence of which the very idea and 

 possibility of evolution depends. The tendency to produce a more 

 numerous offspring gives naturally a larger number of individuals for 

 the exhibition and operation of the laws of variation. The process of 

 cross-fertilisation itself produces another tendency to variation ; and 

 as such variation is the " key-note " of evolution, it is more than 

 interesting to find the conditions of plant-life in such a marked 

 manner contributing to the differentiation of the species. 



The whole array of features embraced in a study of flower-fertilisa- 

 tion forms simply a mass of evidence that the production of new races 

 and varieties, and, through these, of new species, is part and parcel of 

 nature's constitution. On any other supposition, the extraordinary 

 ?rray of contrivances favouring cross-fertilisation and the initiation 

 of variations, is meaningless and utterly inexplicable. The facts of 

 fertilisation, like the stages of development, present us with un- 

 impeachable evidence in favour of the evolution of new races by the 

 modification of the old. Even if a fact here or a detail there may 

 seem to weigh against the theory of development, it must be borne in 

 mind, firstly, that defects and gaps in our knowledge are still realities 

 of biological science ; and, secondly, that the general and in this 

 case the immensely overwhelming probability of nature's and life's 

 methods testifies to evolution as the true way of creation. Mr. Darwin 

 succinctly enough says, that his experiments on intercrossing show 

 that " with animals and plants a cross between different varieties, or 

 between individuals of the same variety but of another strain, give 

 vigour and fertility to the offspring ; and, on the other hand, that 

 close interbreeding diminishes vigour and fertility." And he also adds 

 that such facts " alone incline me to believe that it is a general law 



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