From the cover:
Concerning the character of this book, Nosodes, it may be said that Dr. Allen first, last and all the time, regarded these drugs as homoeopathic and not isopathic, remedies; and prescribed according to the totality of the symptoms. The preliminary remarks, preceding the drugs treated in this book, tell all that we know concerning the source of the provings. Dr. Allen placed great store by this, his final work, which he, we believe, considered his greatest.

About the author:
Henry Clay Allen (1836-1909)
Dr. Henry C. Allen was born in Ontario, Canada. His homeopathic training came from the Western Homeopathic College in Ohio, United States, where he graduated in 1861. The American Civil War lasted from 1861-1865 during which time Allen served as a surgeon. After the war he began to practice his homeopathic art in Cleveland and this coincided with his taking the position of professorship of Anatomy. In 1875 Allen moved to Detroit and at the turn of the decade the University of Michigan made him Professor of Materia Medica. It was in 1892 that Allen went on to help establish the Hering Medical College and Hospital of which he was Dean until he died in 1909.

Classical homeopathy as we know it today was not widely taught in institutions at the end of the 19th century. Most homeopathic colleges were operating with a mindset similar to modern science. The teachings of Samuel Hahnemann as expounded in his Organon of the Medical Art were not embraced as they were seen as archaic and eccentric. It was Dr. Allen who strove to have the Organon brought back into the syllabus in American colleges and for the most part we owe its extensive use at the turn of the 20th century to him. Allen was an advocate of the principles that Hahnemann had established and he upheld them all his life. An example of this is his difference of opinion with J. T. Kent over the latter's publishing of unproven remedies.