This contribution serves as a supplementary volume to the articles by Joseph Schaffer (1930), Franz Weidenreich (1930), and Hans Petersen (1930), which were published in this handbook. Since their publication, the subject matter has not only expanded but has also changed due to new perspectives regarding the composition and structure of the intercellular substances of cartilage and bone tissues. The attempt to relate current knowledge about intercellular substances to morphological findings has delayed the completion of the manuscript. I am grateful to the editor, Professor Dr. Drs. h. c. Wolfgang Bargmann, and the publisher for their patience with me. I would also like to thank all my collaborators who supported me in completing the manuscript, including Dr. Margarete Mohn, Dr. Gerhard Fischer, and Ms. Charlotte G.