Stamp Act (2 of 1899) , Sch.1B, Art.38A— (as inserted by U.P. 2nd Amendment Act, 1997) - Validity, of - Imposition of stamp duty on document evidencing licence or renewal of licence relating to arms or ammunitions under the provisions of the Arms Act, 1959 - Not ultra vires of Constitution. Constitution of India , Art.254, Sch.7 List 3 Entry 44, Sch.7 List 2 Entry 63— Arms Act (54 of 1959) , S.3, S.16, S.17— Arms Rules (1962) , R.4— The Doctrine of 'pith and substance' provides that if, an enactment substantially falls within the powers expressly conferred by the Constitution upon the Legislature which enacted it, it cannot be held to be invalid, merely because it incidentally encroaches on matters assigned to another Legislature. When a law is impugned as ultra vires, the true character of the legislation has to be ascertained and if, on such examination, it is found that the legislation is in substance one on a matter assigned to the Legislature, then it must be held to be valid in its entirety, even though it might incidentally trench on matters which are beyond its competence. In a situation of overlapping, the rule of pith and substance has to be applied to determine to which entry does a given piece of legislation relate. Thereafter, any incidental trenching on the field reserved to the other legislature is of no consequence. ....