THERE MUST BE days, like the last few, for instance, when Maryland Gov. Harry Hughes wonders why he ever paid so much attention to prisons when he first took office. Having run through several dramatic changes of corrections chiefs and having garnered the standard legislative grief that comes from Annapolis with each prisons- policy move, the governor has a new mess on his hands in Baltimore. The Maryland Penitentiary -- where a guard was slain last month -- is a disaster by all official accounts.

On Tuesday, the state attorney general, Stephen H. Sachs, issued a scathing report that faulted mid- level as well as top management at the penitentiary for failing to avert disruption and violence, including the Oct. 6 stabbing of a guard in the infamous South Wing. The report described this wing as a chaotic, foul-smelling, overcrowded facility with an administration that has been slow to make structural improvements and to beef up security.

The next day, a state legislative subcommittee ordered a management audit of the state's prison system after hearing new testimony that inaction and poor supervision have contributed to "zoo- like" conditions at the penitentiary. The subcommittee voted unanimously to direct a state crew to evaluate the competence of top prison officials, as well as to find out what the limited number of guards have been detailed to do in the way of unnecessary clerical or other nonsecurity duties.

So far, Gov. Hughes has acted quickly and firmly, ordering the warden and assistant warden removed and directing corrections officials to complete immediately several security steps. Shouldn't these things have been done long ago? Of course, but they weren't. It doesn't speak well for the long- range outlook if nobody seems to pay attention for more than a week or two when things go alarmingly wrong.

Prisons aren't popular because those who live in them aren't popular. Money and concern are in short supply, and too often, as in the case of the penitentiary, the facilities are too big to work well. Too often the official response to any calamity is 1)to slam everybody into cells and call off paroles, or 2)to go the other way and start letting too many people out early to relieve overcrowding. Until somebody comes up with better, more sophisticated ways to deal with lawbreakers, Gov. Hughes and the legislative overseers should personally monitor the system as closely and continuously as they can.