The writings of the old school, on the other hand, dealt with the nature of the human instrument; they went back to the very foundations of human sound-generation. Nothing was taken for granted, least of all the normal processes of everyday speech. Nothing was described in terms of subjective sensation; in the whole of Manuel Garcia’s writings it is hard to find a single mention of the kind of sensation which a singer may expect to feel when singing. This does not mean that Garcia never used this method of teaching; but it certainly suggests that he realized the dangers of putting sensations into books. The difficulty here is that the sensations of singers arise from a combination of the workings of individual cerebro-nervous systems and an individual gift of what may be termed “sensory awareness”; and the more closely the singer tries to analyse these sensations the more misleading they can be. When a whole group of great singers attests to what may be called an ‘overall’ sensation, the evidence is often of great value, but the process of taking sensations to bits in order to see how they work is dangerous. The great Lilli Lehmann wrote a book on these lines, in which she attempted to clarify the analysis of her sensations by means of a number of carefully executed illustrations in line and colour. The book is quite incomprehensible, even to an experienced singer.
Kelsey, Franklyn. “The Riddle of the Voice.” Music and Letters 29.3 (1948): 238-248.