There has been much talk and squawk for "constructive criticism." It would mean about nothing. By the time it appears, it would have to be reconstructive. And it's then too late. A handful of plays have upset the original opinion, notably _Abie's Irish Rose_, _Tobacco Road_ and _Hellzapoppin'_. In all those instances, and the few others where a production caught its second wind, the backers were game and optimistic, plowed through losses with a confidence rare in such enterprises. As a rule, what the first-nighters say as they come out is final, be it an Ibsen revival or a Theatre Guild musical or a bawdy revue. Word spreads amazingly fast and far. Fifteen minutes after a smash has rung down, the cigar-store crowds in the Bronx and the burghers on Staten Island and the stoop-sitters in far Flatbush are chewing about it. For a big hit is big business in the Big Burg. No recurrent event, including contest sports, sells papers like an important opening. Thousands know that what the critics say means a flop or a run. Not only are many directly interested, but millions follow such news, as Los Angeles reads Hollywood trade matter, Chicago goes for stockyards' statistics, Detroit watches auto output, Washington eats up politics and Memphis seeks the latest on "the state of the River." For the stage is a colossal industry in Greater New York. Its "legitimate" houses turn over more than $1,000,000 a week in good months. Its unions are rich and powerful, its personnel exceeds in volume the population of some metropolitan cities. Yet its fortunes hang on invisible, intangible hairs! 5. SWING LANE In defiance of police regulations, two lines of sleek and fancy limousines are parked nightly outside Jack and Charlie's famed 21 Club in 52nd Street. One reason why the cops close their eyes while pounding that beat is that the cars, with liveried chauffeurs, are owned by the rich and prominent townsfolk. Another is that many of the machines carry burnished seals, signifying they belong to, or at least are assigned to, high city, state and national officials. West of Fifth Avenue, 52nd Street was long a street of wealth. Today, the 21 Club is wealth's last outpost. This was a baronial thoroughfare, lined on both sides by fancy brownstone and brick residences of solid and superior citizens. But the northward encroachment of business, culminating in the late 20's and early 30's with the construction of Rockefeller Center only a block south, drove the householders elsewhere. Many of the luxurious brownstones were converted into rooming houses and made over into one- and two-room apartments; but the chief industry in the block was speakeasies. The street was a natural--it ran in the right direction, i.e., its one-way traffic was routed from west to east, which in midtown New York is important, because the bulk and the best of aftertheatre traffic goes that way.