Under “normal” circumstances the closing of a theatre, even on a short term basis, would hardly be a promising event. Nevertheless. Bill Glassco’s decision to withdraw Toronto’s Tarragon Theatre from active production during the 1975-’76 season may prove an exception to the rule. What’s more. Glassco’s decision is representative of the present state of theatre in Toronto which, indeed, is anything but “normal.” Beneath the ever-increasing quantity of productions encountered with each new season, one senses that a kind of spiritual exhaustion has infected the city’s most important theatres.