It may easily be understood that a retentive memory is of great value to the musician, be he composer or merely performer. Talented young musicians not unfrequently possess an astounding memory. Sonatas, symphonies, and even fugues, which they practise, they can soon play by heart. As they advance in years the power of memory generally becomes somewhat weaker. Blind musicians appear to preserve it undiminished for a longer period than others. The blind flutist Dulon knew 120 flute concertos by heart, which he had numbered, and any one of which he could play instantly on its number being mentioned to him. True, there is musically little gained by burdening the memory with compositions which chiefly consist of compilations of passages calculated to display the dexterity and skill of the performer. The works which the musician ought to be able to recall to his memory are the classical works, such as Gluck's 'Iphigenia in Tauris,' Mozart's 'Don Giovanni,' Beethoven's Symphonies, Handel's 'Messiah,' Bach's 'Passion according to St. Matthew.' There are not a few among our great composers who studied the master-works of their predecessors so effectually that they knew by heart a considerable number of them from beginning to end, with the instrumentation of every bar. As regards the different forms of composition, that of the sonata is the most important; for, if the composer is able to express his ideas with facility in this form, he possesses the key to all the other forms--except some of the older ones, as that of the fugue. Certain theorists recommend the student of composition to select a sonata by Mozart, or some other master, in which the established form is strictly adhered to, and to write a precisely similar sonata by imitating the model bar for bar, using the same time, tempo, modulations, changes in loudness, and so on--only substituting other notes. No doubt he may thus manufacture a sonata which is correct in form, whatever it may be in spirit. Our great composers did not arise from students trained to make music as the shoemaker makes shoes. The form of the fugue has already become antiquated, and that of the sonata is more and more neglected by our present composers, and apparently will likewise become antiquated in the course of time. But until we have beautiful examples of some new form, it is not probable that those forms which have been gradually brought to a high degree of perfection will be entirely dispensed with, whatever modern composers may produce exhibiting an indifference to the rules observed by their predecessors.