The Definitive Kobbe's Opera Book (Edited, Revised and Updated Edition, 1987)

From the 1919 First Edition:
Schools of Opera
THERE are three great schools of opera,—Italian, French, and German. None other has developed sufficiently to require comment in this brief chapter.
Of the three standard schools, the Italian is the most frankly melodious. When at its best, Italian vocal melody ravishes the senses. When not at its best, it merely tickles the ear and offends common sense. "Aïda" was a turning point in Italian music. Before Verdi composed "Aïda," Italian opera, despite its many beauties, was largely a thing of temperament, inspirationally, but often also carelessly set forth. Now, Italian opera composers no longer accept any libretto thrust at them. They think out their scores more carefully; they produce works in which due attention is paid to both vocal and orchestral effect. The older composers still represented in the repertoire are Rossini, Bellini, Donizetti, and Verdi. The last-named, however, also reaches well over into the modern school of Italian opera, whose foremost living exponent is Puccini.
Although Rameau (1683-1764), whose "Castor and Pollux" held the stage until supplanted by Gluck's works, was a native of France, French opera had for its founder the Italian, Lully; and one of its chief exponents was the German, Meyerbeer. Two foreigners, therefore, have had-2- a large share in developing the school. It boasts, however, many distinguished natives—Halévy, Auber, Gounod, Bizet, Massenet.
In the French school of opera the instrumental support of the voice is far richer and the combination of vocal and instrumental effect more discriminating than in the old school of Italian opera...