SOCIAL AND POLITICAL ECONOMY. 193 



changes of which these economic modifications are 

 the results, were slowly acquired, so that a long 

 period of time was occupied in producing them. 

 Many plants are living botanical museums, stored 

 with evidences of past organic changes, either in the 

 shape of newly-acquired or of aborted organs. On 

 the whole, however, it will always be found that these 

 alterations have taken place in the interest of the 

 species and with a view to save them from extinction. 



Take the well-known order of plants Geraniacece, 

 in which the genus Geranmm is chiefly distinguished 

 from Erodmiu by all its species (except the little 

 Geranium picsillmn^ having ten stamens, whilst the 

 latter has only five perfect ones, although the other 

 five are present, but they are imperfect and useless ; 

 in fact they do not bear anthers. Can any one doubt 

 that the Erodiums are merely Geraniums altered by 

 having half their stamens aborted, probably because 

 they were found unnecessary and supernumerary ? 

 What is the good of a plant building up useless 

 tissues and organs ? Such an act is as wise as that 

 of an already hard -worked man, who deliberately 

 puts heavier burdens on his shoulders. 



The importance of accessory parts, such as petals, 

 to all insect -fertilised flowers, has been already 

 shown. But these are modified in a wonderful 

 degree whenever such a change is beneficial — some- 

 times being enlarged, and occasionally aborted. In 

 the natural history economy of plants there are 



O 



