The following amendments have been made to the original text:

• Page 24: “and were the forerunners of the opera and oratorio”
  for “and were the fore-/runners of the opera and oratorio”
• Page 26: “But in that brilliant springtime of vocal art”
  for “But in that brilliant spring-/time of vocal art”
• Page 30: “i. e., the old singing masters taught”
  No comma in original (added for consistency).
• Page 42: “by their anterior apophyses, without leaving any space”
  Comma missing from original.
• Page 48: “vol. x. 4th Series, pp. 218–221, 1855.”
  for “vol. x. 4th Series, p. 218–221, 1855.”
• Page 66: “i. e., those tones where a different action”
  No comma in original (added for consistency).
• Page 79: “the tones of the head register.”
  Period missing from original.
• Page 87: “the reed of the mouthpiece.”
  for “the reed of the mouth-/piece.”
• Page 108: “the air coming from the lungs through the trachea,”
  for “the air coming from the lungs through the treachea,”
• Page 118: “then the high inharmonic over-tones are prominent,”
  for “then the high inharmonic overtones are prominent,”
• Page 132: a¹ accented-b¹ a¹ accented-b¹
  for (compare fourth note)
  a¹ accented-b¹ a¹ accented-a¹
• Footnote 18: “struggle to establish the unity of the fatherland.”
  for “struggle to establish the unity of the father-/land.”