269. Unumquodque dissolvitur eodem modo quo colligatum est. Every obligation can only be dissolved in the same manner as it was created.
Thus a deed can only be revoked by deed, and not by a simple written instrument. This, of course, subject to the ruling of Courts of competent jurisdiction.
270. Utile per inutile non vitiatur. That which is useful is not vitiated by that which is useless.
Where the meaning of any document is clear, its effect is not marred or upset by the insertion therein of superfluous and meaningless words.
271. Valeat quantum valere potest. Let it stand as far as possible. Let it pass for what it is worth.
(See Max. No. 211.)
* 272. Verba chartarum fortius accipiuntur contra proferentem. Words of deeds or grants are to be taken most strongly against the grantor.
Thus, a rent of 10s. granted by tenants in common is several, and the grantee will have 10s. from each: aliter if a rent of 10s. be reserved. This principle does not apply to a grant by the Crown at the suit of the grantee. Nor must such a rule of construction be followed till all others fail, for the law supposes that a person will not use language to his own detriment. (See Chitty on Contracts, 16th ed. p. 113, and Maxs. Nos. 18 and 207.)
* 273. Verba debent intelligi cum effectu, ut res magis valeat quam pereat. Words ought to be understood with effect, that a thing may rather be preserved than destroyed.
(See Roe v. Tranmarr, 2 Sm. L. C. 506.) This rule is closely allied to Benignae faciendae sunt interpretationes chartarum ut res magis valeat quam pereat. (The construction of deeds shall be made liberally that the subject-matter may rather prevail than perish.) Construction must in all cases be reasonable, liberal, and favourable. (See Chitty on Contracts, 16th ed. p. 97, and Maxs. Nos. 26, 78, 145, and 275.)