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forms and qualities which better enable them to minister to man’s 
wants, than the species from which they were originally derived. Until 
recent times—for it is but lately, as I stated at the outset, that the nature 
of the sexes of plants was clearly understood—men had to take advan¬ 
tage of any deviation which appeared in their crops naturally, or as the 
result of improved culture; and if the cultivator wished to perpetuate 
an improved variety, or obtain others better, he grew and seeded the 
plants alone; and if any seedling was better than the parent, that only 
was saved; seed from it was sown, the first plant again selected, and so on 
through successive generations. This is even now found a useful mode 
of proceeding, and is practiced with some plants by men who are adepts 
at cross-breeding. Andrew Knight in this way obtained a very early and 
hardy variety of the cabbage, which in his hands continued yearly to 
Improve in these useful properties, but greatly degenerated in the hands 
of the seedsmen owinof to their want of care or skill in selecting seed- 
o o 
bearing plants. Skirving’s Swede turnip has obtained a wide celebrity, 
he is understood to have raised the variety to its present excellence by a 
careful selection of roots to produce his annual supply of seed. The im¬ 
portance of attending to the improvement of agricultural plants by this 
means might seem from the following passage in Virgil to have been bet¬ 
ter understood or practiced by the Romans 2000 years ago, than at the 
present day: 
Oft have I seen the chosen seed deceive, 
And o’er degenerate crops the peasant grieve ; 
Save where slow patience o’er and o’er again, 
Culled yearly one by one the largest grain. 
The method of improving plants now most generally and successfully 
practised, is that of cross-breeding and hybridizing. By cross-breeding 
is understood crossing between two varieties of one species, as between 
two kinds of the apple; by hybridizing breeding between two distinct 
species of one genus, as between the apple and the pear—plants, like 
animals, will only breed within certain limits. Varieties cross readily 
with each other ; hybridizing is a much more difficult matter to accom¬ 
plish. Ko one has been able to cross the apple with the pear, nor the 
currant with the gooseberry. The morello-was made by Andrew Knight 
to breed with the common cherry—two distinct species—the offspring 
proved to be true mules, producing abundance of blossoms but no fruit.. 
Some hybrids breed if crossed again with one of the parent plants, some 
