82 JOURNAL OF THE ROYAL HORTICULTURAL SOCIETY. 



rears' cultivation. Brassica nigra of Europe becomes B. bracteolata in 

 Egypt &c. 



The fact is that the composite nature of an artificially prepared soil 

 acts as a powerful stimulus to variability, so that the living protoplasm 

 responds at once, and the result is a new form in harmony with the 

 environment. 



A good illustration is seen in our kitchen garden root crops, as the 

 Carrot, Parsnip, Radish, Turnip, and Beet. 



^VYith the exception of the last, all the others are annuals. In order 

 to convert them into biennials the vegetative system is so stimulated that 

 the reproductive process is delayed, and by sowing the seed of the wild 

 plant late in the season it cannot flower the same year. Hence it has, so 

 to say, a season and a half for the foliage to make a superabundance of 

 food materials which have to be stored up in the root, which is now 

 greatly enlarged to receive it. 



The same effect is produced on the Beet and Mangold Wurzel when 

 raised from the seed of the wild plant ; though it is naturally a perennial, 

 which thus becomes changed into a biennial. 



Now this biennial " habit " has become fixed and hereditary as well 

 as the " forms " of the roots. 



The way to express this is precisely the same as when a variety or 

 species is formed in nature, viz. the plant by means of its protoplasm 

 responds to the direct action of the environment, and is developed accord- 

 ingly into a fleshy root, and so forms the kitchen garden vegetable. 



Similarly is it, cceteris paribus, with Cabbages, Onions, and all other 

 kmds of vegetables, in which various parts of the plants have altered and 

 become fixed features in each kind respectively. 



We thus learn, first, by inductive evidence, from the study of the distri- 

 bution and structure of organisms in nature that they arise by a process of 

 self-adaptation or response to the direct action of the changed conditions 

 of life ; that if many seedlings appear of any one kind they all grow up 

 alike, or, as Darwin expresses it, they " vary definitely." 



As more are born than can live, natural selection stands for the sur- 

 vival of the strongest and the destruction of the weakest, but has no 

 opportunity of " selecting " with the view of originating a new variety, 

 since they all vary alike. 



Inductive evidence having been first established, it can often be 

 followed by experimental verification under cultivation and domesti- 

 cation. 



The ultimate origin of adaptation resides in the living protoplasm 

 and its nucleus. These are endowed with a " responsive power," so that 

 when stimulated the cells give rise to different tissues, and the tissues 

 form differently shaped organs. These latter suggest to systematists 

 different terms in describing the organism as a sub-variety, variety, 

 species, or genus. 



Given, then, the first atom of living protoplasm with its nucleus, the 

 whole of the vegetable and animal kingdom, including man, have issued 

 from it. Protoplasm is practically omnipotent, not only in making new 

 creatures, but in adapting any organ to a variety of purposes, as well as 

 any organs for one and the same, if it be so desirable. 



