i64 PRESENT-DAY RATIONALISM 



because the climate of Egypt has never altered. If seeds, 

 however, be transferred to some quite new and different climatic 

 conditions they are often found to vary very much as they grow 

 to maturity. In agreement with this it has often been observed 

 that most varieties are found on the confines of the geographical 

 areas of any particular plants. 



Hence is the discovery that organisms are mostly very 

 plastic and possess "variability," i.e., a capacity for varying 

 which is incited into action by the direct influence of the 

 environment. 



Coupled with the power to vary from the characters of the 

 parents, offspring always have a tendency to reproduce the 

 parental form, so that they grow up under the two antagonistic 

 influences, viz., atavism or heredity, and variability. 



In studying the variations of animals and plants under 

 domestication, Darwin noticed that offspring seemed to vary 

 " indefinitely," as he called it ; that is to say, when a large 

 number, say, of seedlings, are raised in a border, though the 

 majority resemble the parent, several may differ more or less 

 obviously from the parental type. If the raiser see one which 

 he thinks will be of advantage to him, he will " select " this 

 individual, either by removing all others from its neighbour- 

 hood and letting it grow by itself; or he removes the plant to 

 a locality far away from the rest, so that no insects may cross 

 it with pollen from others of the same species, but unlike the 

 particular individual. This is called "artificial selection ". 



Now, it is the peculiarity of the artificially prepared soil of 

 a garden with its variety of ingredients, to so stimulate the seed 

 of a wild i)lant sown in it (which may never vary at all in 

 Nature, as the cabbage), that its seedlings may grow up 

 into several and differently constructed plants. Thus, to give 

 two examples : M. Carri^re ^ cultivated the wild radish, Raph- 

 anus Raphanistrum. In a few years he obtained the garden 

 or " ameliorated " forms of root, and he found that by sowing 



' Origine des Plantes Domestiquts demontrce par la Culture du Radii 

 Sauvage. 



