Please Email comments or suggestions to:curtin@nku.edu
You may view the four pages of the 1906 paper that do not appear in the 1904 version.
The 1906 reference is Helge von Koch, " Une méthode géométrique élémentaire pour l'étude de certaines questiones de la théorie des courbes planes,'' Acta Mathematica, 30 (1906), 145-174. You have Vardi's translation of pp. 145-170. I scanned the last four pages as JPEG images. You can read them in your browser, or print them out. I used a scale factor of 75% to print them, but this will vary with your equipment.
Dan Curtin