May 9, 1902.] 



SCIENCE. 



727 



species. Perhaps the first is, because of 

 its broader leaves and stouter stem, a little 

 better adapted. Probably both would 

 survive in the struggle for existence if the 

 early stages v^ere not detrimental. 0. 

 alhida and 0. oblonga, on the other hand, 

 are extremely weak, and it is with great 

 difficulty that they can be persuaded to 

 produce flowers and fruit. When growing 

 wild they could never survive, in fact, they 

 are never met with, though in the garden 

 experiments they made their appearance 

 in large numbers. For 0. nanella the 

 form is an objection, at least, under exist- 

 ing conditions, though were these different, 

 it might prove an advantage. In regard 

 to 0. lata, which ^^ntil now I have hardly 

 mentioned, the plants are low, with a limp 

 stem, bent tips and side branches, all very 

 brittle, but with dense foliage and luxu- 

 riant growth. But unlike its relations, it 

 possesses no pollen. It is true there are ap- 

 parently robust anthers, but they are dry, 

 wrinkled and devoid of contents. Only by 

 cross-fertilization can 0. lata produce seeds, 

 and so it is unfit to found a wild type. 

 Certain structural characters of this plant 

 are therefore detrimental, or at least use- 

 less, and 'useless charactei-s, ' as every one 

 knows, were among the earliest objections 

 to the doctrine of the gradual origin of 

 species by selection. For this theory can 

 explain none but useful characters. 



These observations are also important 

 from another point of view. They teach 

 us that the variability of species is inde- 

 pendent of environment. This hypothesis, 

 already formulated by Darwin, and which 

 for him was the basis of a simple, logical 

 explanation, is fully confirmed by the re- 

 sults of our experiments. Before Darwin 

 published his 'Origin of Species,' it was 

 generally believed to be otherwise; it was 

 thought that environment had a direct in- 

 fluence on species. Changes in environ- 

 ment would call forth various needs and 



these in their turn would cause gradual 

 changes in various organs. Use would 

 have a strengthening, disuse a weakening, 

 effect; a functioning in a certain direction 

 would fit the organ better for that func- 

 tion. The changes would take place grad- 

 ually and imperceptibly, but if only the in- 

 fluence continued long enough in one direc- 

 tion, specific differences would finally 

 appear. On this theory are based the 

 attempts already mentioned to make new 

 species by transporting lowland plants to 

 the highlands and vice versa. When this is 

 done, great modifications may be observed, 

 even during the first year. In the Alps 

 the plants assume the compact, woody, 

 small-leaved form which we meet with there 

 so frequently; in the plains they are tall, 

 with slender stems and ample but delicate 

 foliage. At first it appears as if these 

 experiments bore out the general opinion, 

 but Bonnier has shown the opposite. He 

 has proved that it is nothing but adapta- 

 tion, something which any plant can show 

 and which stands in no relation to hered- 

 ity and the origin of species. 



In my experiments the mother species 

 mutates in all directions, in nearly all or- 

 gans and characters as well as for better 

 or worse. These changes occur, as far as 

 could be learned, on a poor sandy soil as 

 well as on heavily manured garden soil, 

 with careful treatment and plenty of room 

 between the plants. The mutation there- 

 fore is independent of environment, its 

 direction is not governed by circum- 

 stances. Numerous species originate at 

 the same time, forming a group in the same 

 manner as the above-mentioned genera. 

 The question which of these will persist in 

 the wild state, which, as legitimate species, 

 will some time form part of our flora, does 

 not concern us at present. This can only 

 be decided when the new forms have lived 

 next to the others for a prolonged period, 

 as some of them have done for the last 



