i82 NATURAL SCIENCE. Sept.. 



direct relation to the mere fact of insects crawling over them or 

 settling upon them. So also are those varied adaptations by which, 

 as Kerner has shown, injurious insects are prevented from reaching 

 the flowers. 



Even more unintelligible on this theory are modifications of 

 fruits and seeds, by which some attract birds or mammals to eat 

 them, while others are guarded against being eaten ; some seeds have 

 beautiful wings or plumes for wind dispersal, others have hooks or 

 sticky hairs which cling to wool or feathers, while others again are 

 scattered abroad by the sudden elastic bursting of the capsules. 

 Take the comparatively simple case of nuts. Did they acquire their 

 hard covering and brown protective tints and detachment from the 

 tree as soon as ripe by the direct agency of birds, or monkeys, or 

 squirrels ? Of course, the question is absurd, since those eaten by 

 these creatures could not transmit their special qualities ; but those 

 that, by the possession of any of these qualities, escaped being eaten, 

 would transmit those qualities to the next generation. 3 



Any conceivable direct action of the environment can therefore 

 have produced only a very small portion of the modifications and 

 adaptations that actually exist. In by far the larger number of cases 

 no such explanation is possible, and no other adequate explanation 

 has been suggested except variation and Natural Selection. It is, of 

 course, admitted that the action of the environment does produce 

 definite changes in all organisms, more especially in plants, but there 

 is no evidence that such changes are transmitted to the offspring of 

 the individuals in which they have been produced. 



On the other hand, there is direct evidence that many such 

 changes are not transmitted, an example of which is the Arabis 

 anachoretica with remarkable tissue-papery leaves, due to its growth in 

 hollows of the rock, where neither sun nor rain reach it. Seeds of 

 this plant when cultivated at Kew produced the common Arabis 

 alpina. The same thing occurs with many plants, as every cultivator 

 knows ; but other forms with no greater peculiarities externally 

 preserve their characters under cultivation, though exposed to the 

 most varied conditions. As we thus know that some variations 

 directly due to the environment are not transmitted, and also know 

 that an immense number of spontaneous or congenital variations are 

 transmitted, since by taking advantage of this fact almost all the 

 improvement in our domestic animals and cultivated plants 

 has been effected ; and yet further, that no case has been found in 

 which such spontaneous variations are wholly intransmissible, — the 

 logical conclusion is that the two kinds of variation are distinct in 

 their nature. This view of the subject is adopted by those botanists 

 who are now endeavouring to determine the true nature of the 



^ Other cases of the want of relation between adaptations and their supposed 

 cause are given in my article, " Are Individually Acquired Characters Inherited? " 

 in the Fortnightly Review' of May, 1893, pp. 664-9. 



