An occasion of deep interest and of more than common significance will occur presently at Cambridge, Mass. Henry Irving has been invited to speak at Harvard University, on the general subject of the stage and dramatic art, and he has accepted the invitation. Mr. Irving's address will be delivered in the Sanders Theatre, on Monday, March 30. The actor's art could not have a more authoritative voice to speak its mission and advocate its cause. The audience will be worthy of the speaker, for it will represent one of the foremost institutions of learning and one of the most refined and cultivated communities of this country. Harvard University listening to a great and famous actor descanting on an art that once was forbidden under the laws of Massachusetts, but which he and men like him have made powerful and illustrious, will present an impressive spectacle.- N. Y. Tribune.