clause itself falls short of furnishing a complete and sufficient protection. A constitutional provision is sometimes, of itself, a complete law for the accomplishment of the purpose for which it was established, and sometimes it merely declares a principle which will be dormant until legislation is had to give it effect. When the former is the case, the provision is sometimes spoken of as 'self-executing.' Nearly all the provisions of the federal constitution which confer legislative or judicial power are inoperative for the practical purposes intended, until legislation under them has given the means, and pointed out the methods, by which the powers shall be exercised. * * * A prohibition of a power in the federal constitution defeats any attempt of its exercise; and any court, state or federal, that may have cognizance of a case in which the power can come in controversy, whether directly or incidentally, must take notice of and act upon the prohibition. Thus the mere declaration that 'no bill of attainder shall be passed' has been found ample to protect all the people against legislative punishment in cases not within their proper cognizance, though no legislation has ever been had looking to its enforcement. The case of the prohibition of the laws impairing the obligation of contracts is a still more strong illustration of the force of certain provisions standing independently. In a multitude of forms, laws have appeared which were supposed to violate this provision; and in no case has a court, either state or national, had any difficulty in dealing with it, or in declaring the law null if it was believed to be within the prohibition. Such a provision may well be declared self-enacting. It is a complete and perfect law in itself, which all courts must take notice of, and enforce, whenever a disregard of it comes to their judicial notice, without any statute requiring or expressly permitting it." Williams v. Mayor, 2 Mich. 560, was an action brought to restrain the collection of an assessment imposed, by order of the mayor and board of aldermen of Detroit, upon a certain-lot; and the first ground urged for the restraint was that such an assessment was unconstitutional and void. The court, on page 565, says: "§ 11, art. 14, reads as follows: 'The legislature shall provide an uniform rule of taxation, except on property paying specific tax, and taxes shall be levied on such property
