Note 6 — INTRODUCTION.
Reading edition
Mr. Darwin’s attention was called by Professor Hensen to P. E. Müller’s work on Humus in ‘Tidsskrift for Skovbrug,’ Band iii. Heft 1 and 2, Copenhagen, 1878. He had, however, no opportunity of consulting Müller’s work. Dr. Müller published a second paper in 1884 in the same periodical—a Danish journal of forestry. His results have also been published in German, in a volume entitled ‘Studien über die natürlichen Humusformen, unter deren Einwirkung auf Vegetation und Boden,’ 8vo., Berlin, 1887.