There is, in law, no such thing as a legal dead letter. That is, it is not open to the courts to refuse to implement a statutory provision, purely on the ground that it has fallen into disuse or has been forgotten.
What of the Public Health (Ireland) Act of 1878 ((41 & 42 Vict.) c. 52)? It was recited in the First Schedule of the Statute Law Revision Act 2007 and was, consequently, retained as law in Ireland.
Before that, Section 54 of the Public Health (Ireland) Act 1878 was specifically brought into force in the County Health District of Dublin by the provisions of S.I. No. 310/1970.
Consequently, Section 54 of the Public Health (Ireland) Act 1878 appears to be still in force in [South Dublin County], [Fingal County] and [Rathdown County]. (County Dublin, excluding the City of Dublin).
The Public Health (Ireland) Act 1878 was the enabling provision for the Dublin Corporation Bye Laws of June1899 referred to HERE.
What happened, then, to those Bye Laws on the repeal of Section 54 of the Public Health (Ireland) Act 1878 in 1996?
They were, in the absence of any saving provision, implicitly revoked.
What alternative provision did Dublin City Council introduce? It had that power under Section 37 of the Local Government Act 1994.