And when a cross has been made, the closest selection is far more indispensable even than in ordinary cases.

If selection consisted merely in separating some very distinct variety and breeding from it, the principle would be so obvious as hardly to be worth notice; but its importance consists in the great effect produced by the accumulation in one direction, during successive generations, of differences absolutely inappreciable by an uneducated eye--differences which I for one have vainly attempted to appreciate.

Not one man in a thousand has accuracy of eye and judgment sufficient to become an eminent breeder.

If gifted with these qualities, and he studies his subject for years, and devotes his lifetime to it with indomitable perseverance, he will succeed, and may make great improvements; if he wants any of these qualities, he will assuredly fail.

Few would readily believe in the natural capacity and years of practice requisite to become even a skilful pigeon-fancier.
The same principles are followed by horticulturists; but the variations are here often more abrupt.