WHEN I began my metabolic researches of the inner ear some ten years ago,1 I found a great many problems to be solved, and every study meant exploring new and unknown areas. It did not matter which of the many metabolites were chosen for study. Since I was interested in the metabolism of proteins and ribonucleic acids (RNA) in other organs, I selected these substances for my work. Carbohydrates and fats have been shown to be the principal sources of cellular energy. Proteins determine chiefly the specific function of each cell. They are the basic elements of the protoplasm and form the building stones which are necessary for the synthesis of organic structures.
Delicate changes in the structures of a cell cannot be demonstrated by the techniques of decalcifying and embedding the temporal bone in celloidin. Thus we had to find a suitable method of demonstration for the purpose