264 THE EVOLUTION THEORY 



bears no relation to the grade of organization of the young creature 

 that is to arise from it, but is clue solely to the special conditions 

 imposed on the particular germ-cell, if a young organism is to be 

 evolved from it. We shall soon see what is meant by this. 



I must note here that plants and animals do not multiply by means 

 of germ-cells alone, but that many species — the majority of plants 

 and the simpler forms of animals — also exhibit multiplication by 

 budding or division. All animals and plants which do not stop short 

 at the stage of the individual, the ' person,' but rise to the higher 

 stage of the ' stock ' (or corm), illustrate this. The first person from 

 which the formation of the stock proceeds gives rise by budding or 

 division to new persons which remain attached to it, and in turn by 

 repeated production of buds give rise to a third, fourth, or n {h 

 generation of persons, all remaining in connexion with the first, and 

 together forming the composite individuality of the animal-colony or 

 plant-stock. Such colonies or stocks are seen in polyps and corals, 

 Siphonophorae and Bryozoa, and among plants, according to Alexander 

 Braun, in all phanerogams which do not consist only of a single 

 shoot. In these cases we find that definite, or perhaps indefinite 

 groups of cells in the stock may give rise to a new person, and we 

 have to inquire how this power may be theoretically interpreted. 



New stocks may also have their origin from such buds, or from 

 single persons of the stock. The fresh-water polyp (Hydra) gives 

 rise by budding to a small stock of at most three or four persons ; 

 but the young animals budded off only remain attached to the 

 parent hydra until they have attained their full development ; then 

 they detach themselves and settle down independently, and begin 

 to bud off in turn a similar and transitory stock. Among plants 

 there are many which, like Dentaria bulhifera and Marcliantia 

 polymorpha, multiply by so-called 'brood-buds,' that is, buds which 

 fall from the stock and grow into new plants. The whole horti- 

 cultural propagation of plants by cuttings also depends on the process 

 of budding, for what is cut off from the parent plant and stuck into 

 the earth is a single shoot, that is, a ' person ' which possesses the 

 power of sending down roots into the earth, and by continual budding 

 giving rise to new shoots or persons which together make up a new 

 plant-stock. 



I must not, however, spend much time over this so-called 

 ' asexual ' reproduction by budding and division, because it does not 

 suggest any way by which we may penetrate more deeply into the 

 processes of inheritance, and we may be content if we can bring them 

 into harmony with other theoretical views which we deduce from 



