between a plea requiring amendment of the plaint and a plea sought to be introduced by way of a replication was noticed as under: “17. A distinction between a plea requiring amendment of the plaint and a plea sought to be introduced by replication shall have to be kept in view. A plea which essentially constitutes the foundation of a claim made by the plaintiff or which is essentially a part of plaintiff's cause of action cannot be introduced through a replication. As already stated replication is always a defensive pleading in nature. It is by way of confession and avoidance or explanation of a plea raised in defence. It will be useful to quote from Halsbury’s Laws of England (Volume 36, para 62, page 48):- “62. Necessity for amendment. The fact that a party may not raise any new ground of claim, or include in his pleadings any allegation or fact inconsistent with his previous pleadings, has been considered elsewhere. In order to raise such a new ground of claim, or to include any