46 THE BIOLOGICAL PROBLEM OF TO-DAY 



doubling division that is, of division in which the 

 germinal substance is handed on to every part of 

 the organism. Our review may be short, as the 

 phenomena are matters of common knowledge. 



In nearly all plants there exist, widely spread 

 through the body, cells and cell-groups, which may 

 be induced, by inner or outer influences, to give 

 rise to a bud ; the bud grows out into a shoot, 

 ultimately producing flowers and genital products. 

 Such happens both in parts of the plant above the 

 ground and below it ; in the latter case shoots 

 arise from roots, and reproduce the species in the 

 ordinary sexual fashion by bearing sexual products. 



Thus, in the case of Funaria hygrometrica, a 

 little moss, one may chop up the plant into tiny 

 fragments, scatter these on damp earth, and see 

 numerous moss-plants reproduced from the little 

 groups of cells. By cutting little pieces from a 

 willow, an experimenter may cause the production 

 from slips of thousands of willow-trees, each with 

 all the characters of the species, so that there must 

 have been contained in each of the little pieces of 

 tissue hereditary masses with the characters of the 

 whole plant. Separate pieces of the leaves of many 

 plants, as of the begonia, produce buds from which 

 the whole plant may grow out. 



An aptitude for reproduction like that in plants 

 exists in many ccelenterates, worms, and tunicates. 

 The polyps of hydroids and of bryozoa, the stolons 

 of an ascidian (Glavellina lepadiformis), may give 

 rise to buds in many places, and these grow up 

 into the perfect hydroid, bryozoon, or ascidian. 



