(3) PAIS, or BY CONDUCT. At present, this is by far the most extensive of the three classes of estoppel, although in Lord Coke's time it was limited to estates in land acquired by livery of seisin, by entry, by acceptance of rent, and by acceptance of an estate.
Estoppels by record and estoppels by deed are often spoken of as 'odious,' because, being of a technical character, they operate harshly at times. Estoppels in pais do not rest upon con siderations of general policy, such as have led to the establishment of the other classes, but upon the doctrine that where one by his conduct causes another to believe the eecistence of a certain state of things, and induces him to act on that belief so as to alter his previous position, the former is precluded from averring, as against the latter, that a different state of things existed at the time in question. These estoppels are treated with favor by the courts, and their scope is increasing constantly. They are known also as 'equitable estoppels' and have their founda tion in fraud. But while the conduct which produces an estoppel in pais is generally fraudu lent, it is not always nor necessarily of that character. An example is afforded by one who withdraws from a partnership. He must give notice of Ids withdrawal or lie will he estopped from showing that he lias ceased to be a member as against one who has become creditor of the firm upon the assumption that lie was still a member. Nor will it be av defense that. his
former partner agreed to give the proper notice of dissolution. It is Ids duty to he active in the matter; to see that such notice is given as will in the ordinary course of business protect third persons from trusting the tiro on the assumption that lie is still a partner, The modern American doctrine of title by estoppel has more in common with the estoppel in pais than with that by deed. Tt arises where an interest in land is purported to be conveyed by deed and the deed emita ins a covenant of war ranty or equivalent covenant of title. Such a deed, though made by one having no estate to convey, vests the title by anticipation in the grantee, which becomes a valid and effectual title if at any time thereafter the land should come to the grantor, no further conveyance being neces sary to divest the title of the grantor or to con firm that of the grantee. This doctrine is pe culiar to the United States. (See FawFsENT: WARRANTY.) Consult: Blackstone, Commenta ries on the Lairs of England (London, 1SSG); Bigelow, Treatise on the Lam of Estoppel (5th ed., Boston, 1890) ; Ewart, Exposition of the Principles of Estoppel by 3/ isrepresentat ion (Toronto, 1900).