198 NATURAL INHERITANCE. [(HAP. XII.
them will betray itself in their offspring. The children of the former.will tend to regress ; those of the latter will not. The value of a good stock to the wellbeing of future generations is, therefore obvious, and it is well to recall attention to an early sign by which we may be assured that a new and gifted variety possesses the necessary stability to easily originate a new stock. It is , its refusal to blend freely with other forms. Some among the members of the same fraternity might possess the characteristics in question with much completeness, and the remainder hardly' or not at all. If this alternative tendency was also' witnessed among cousins, there could be little doubt that the new variety was of a stable character, and therefore capable of being easily developed by interbreeding into a pure and durable race.