198 COLIN CLOUT'S CALENDAR. 



parent stock of all the plums, apricots, and cherries. 

 What nature thus did before by her slow selection, man 

 has merely continued to do more rapidly by his quicker 

 and exclusive methods. Only, man concentrates his at- 

 tention on one single point alone the succulent fruit ; 

 nature equally favors every useful variation in stem, leaf, 

 flower, fruit, or seed alike. Hence it happens that 

 while the wild cherry differs slightly from the blackthorn 

 in almost every particular, the greengage differs from 

 the damson almost exclusively in the fruit, every other 

 part remaining essentially identical. If cultivated plums 

 are allowed to sow themselves and run wild at the pres- 

 ent day, they retain their tree-like form, but revert 

 rapidly to the bullace type. If long permitted to con- 

 tinue wild, however, they show a tendency at last to go 

 back even to the parent south European blackthorn. 

 Their acquired habits are not yet sufficiently ingrained 

 in the race to constitute them a good and permanent 

 species. 



