They contain carbon, hydrogen, oxygen and nitrogen and usually sulfur, occasionally phosphorus. Proteins form a large and essential part of the body mass, comprising especially cell membranes, connective tissue, muscles, enzymes, hormones, blood proteins. To maintain this mass the diet must contain a high proportion of protein, especially in growing animals and those recovering from debilitating diseases.
Russian composer Sergei Prokofiev wrote Peter and the Wolf in 1936 after returning to Moscow following a 19-year, self-imposed exile. It is a children's musical story that teaches about the orchestra by introducing various characters portrayed by seven themes played on either solo instruments or groups of instruments.
BartÃ³k, however, seemed reenergized by his visit with Koussevitzky, and began work on the Concerto for Orchestra the following month. Working at a private sanatorium at Saranac Lake in upstate New York, the composer was able to complete the Concerto in only two months. He wrote to his son Peter on September 26: