There are but two principle methods of cure: the one based only on accurate observation of nature, on careful experimentation and pure experience, the homoeopathic (before we never designedly used) and a second which does not do this, the heteropathic or allopathic. Each opposes the other, and only he who does not know either can hold the delusion that they can ever approach each other or even become united, or to make himself so ridiculous as to practice at one time homoeopathically at another allopathically, according to the pleasure of the patient; a practice which may be called criminal treason against divine Homeopathy.

Organon #5. Sixth edition