When you sing in the manner just described [in the previous posts], you are managing your voice exactly as the old masters taught their pupils to do. This does not mean, of course, that you are using your voice perfectly. But this manner of managing the voice, if practiced daily under proper conditions, will lead to perfect tone production. Three things are needed to train the voice correctly by the natural instinctive system. These are, first, a clear mental idea of perfect tone; second, a well-trained ear, capable of conceiving perfect tones, and of critically judging the tones produced by the voice; third, daily practice in singing tones of the type recognized by the ear as correct. 

In the practical system of instruction perfected by the old Italian masters these three elements of vocal cultivation were combined. That part of the method which has been preserved – the standard collections of exercises and vocalises, represents only the third element. The other two received the necessary attention in the course of the instruction and practice on the composition chosen for study. The old masters recognized, just as well as we do, the necessity for securing the correct management and control of the voice. They summed up their instruction for this purpose in the simple maxim, “Listen and imitate.” At each lesson the master sang, with correct tone, the exercises given to the pupil. Listening closely to the teacher’s tones, the pupil knew how the voice should sound in singing the passages. This secured a gradual training of the pupil’s ear, and made him familiar with the correct standards of vocal tone. HIs memory of the teacher’s  tones helped him in forming his mental ideal of vocal perfection.  Moreover, the student was constantly reminded to listen closely to his own voice, and this was also a valuable form of ear training. In his daily practicing of his studies the student gave his voice the exercise necessary for its gradual development, and at the same time his ear and his mental conception shared in the benefits of the exercise. 

Natural singing, with no definite plan or purpose of vocal advancement would never lead to correct tone production. But when the training of the ear is combined with daily practice in natural singing, and a clear mental conception of perfect vocalism is always held in imagination as the standard toward which the voice is called upon to strive, then correct tone production is readily attained. This was the basis of the old Italian method. It was at once a simpler and a more interesting system than the modern method of conscious vocal management. 

Taylor, David C. “Natural Singing and the Old Italian Method.” Etude Magazine, August 1916: 594.