102 THE THEORY OF MUTATIONS 



controversy. I must now devote a short space 

 to explaining, in as simple language as possible, 

 the facts upon which his theory is based. 



In the first place it seems to be quite clear that, 

 amongst plants at least, new elementary species 

 are produced, and that the history of some of 

 these is quite well known and quite unmistake- 

 able. De Vries gives several instances, one of which 

 will suffice. It is the case of the cut-leaved variety 

 of the greater celandine, a plant which will be 

 familiar to everybody with any knowledge of wild 

 flowers. This species, Chelidonium laciniatum, was 

 first seen in 1590 in the garden of one Sprenger, 

 an apothecary of Heidelberg, who had for years 

 cultivated the ordinary Chelidonium majus, or 

 greater celandine. Sprenger recognized that some- 

 thing new to him had appeared in his garden, and 

 sent specimens of it to the leading botanists of the 

 day, including the celebrated Caspar Bauhin. All 

 agreed that it was a new plant. Much interest 

 was felt in it, and it was introduced into most of 

 the botanical gardens of Europe. At the same 

 time botanists and whatever may have been the 

 state of other sciences, field-botany then was in a 

 more flourishing state than it now is made 

 search for this new plant in a wild state, but with- 

 out any success. It seems to be quite clear that it 

 actually did arise for the first time in the year and 

 at the place mentioned. From the botanical gar- 

 dens it spread to ordinary gardens, and from them 

 it escaped and became a wild plant, and is now 

 almost as common in many places as the older 

 great celandine from which it originated. 



