This paper begins from a discussion of the terms currently applied to the preparations used in homeopathic practice and relates them to the names given to them by Hahnemann, the founder of homeopathy. The latter were directly related to the notion of matter Hahnemann held, this is discussed as it evolved from the earliest sources to the sixth and final edition of the Organon of Medicine, through all the editions of this work as well as many other hitherto rarely explored sources. This review shows that Hahnemann moved conceptually within the field of concepts of late 18th- early 19th century science. This is only natural, and, a legitimate object for studies of the history of science and medicine.