Section 30. If the estate of a devisee under a will is taken for the curtesy of the husband or dower of the widow of the testator, all the other devisees and legatees shall contribute their respective proportions of the loss to the person from whom the estate is so taken, so that the loss may fall upon all the devisees and legatees in proportion to and not exceeding the value of property received by them under the will; but no devisee or legatee shall contribute if exempted therefrom by the will.