The cancellation or reduction of a specific legacy because the subject matter of the gift is no longer part of the testator's estate at his death, or the testator no longer has power to dispose of it, or there is nothing conforming to the description of it in the will. For example, if the will bequeaths a particular house that the testator sold during his lifetime, or if after making a will giving a legacy to his child the testator gives the child property constituting a portion, the legacy is in each case adeemed. The gift of the house is cancelled and the child's legacy is reduced by the amount of the portion (see also satisfaction). Ademption need not occur by the testator's own deed; for example, an Act of Parliament that nationalized a company in which the testator had shares would cause a legacy of those shares to adeem. Neither a general legacy nor a demonstrative legacy can be affected by ademption. An express clause in a will may provide the legatee with a substitutional legacy if ademption should occur.