Instatons, the quark model, and the 1/N expansion

An attempt is made to resolve certain discrepancies between instatons, the quark model and the 1/N expansion. It is argued that the most attractive resolution of these discrepancies is the possibility that quantum corrections cause the instanton gas to disappear in QCD. A two-dimensional model is described in which it can be seen explicitly that such a disappearance takes place. (This model has been investigated independently by D'Adda, Di Vecchia, and Lüscher.)