Physiology of the Opera by John H. Swaby describes the opera and its actors in great detail—on the stage and behind the curtains. Excerpt: As an introduction to the dissertation upon which we are about to enter, such an antiquarian view of the subject might be taken as would tend to establish a parallel between the ancient Greek tragedy and the modern sanguinary Italian opera, the strong resemblance therein being displayed of Signor Salvi trilling on the stage, to the immortal Thespis jargoning from a dung-cart. But we shall indulge in no such wearying pedantry. Our intention being merely to 'hold the mirror up to nature,' in presenting our immaterial reflector to the public, we invite our readers to a view of the present only—a period of time in which they take most interest, since they adorn it with their own presence.