Zoonomia

Zoonomia; or the Laws of Organic Life (1794-96) is a two-volume medical work by Erasmus Darwin dealing with pathology, anatomy, psychology, and the functioning of the body. Its primary framework is one of associationist psychophysiology. The book is now best remembered for its early ideas relating to the theory of evolution, specifically forms of developmentalism similar to Lamarckism. However, despite Erasmus Darwin's familial connection as grandfather to Charles Darwin, the proto-evolutionary ideas in Zoonomia did not have a lasting influence. The first volume, published in 1794, is divided into 40 sections, on a range of topics related to the body, the senses, and disease. He classifies bodily and sensory motions as "irritative," "sensitive," "voluntary," and "associative." He presents theories on the production and classes of ideas, and seeks to explain the causes and mechanisms of sleep, reverie, vertigo, and drunkenness. He then discusses anatomy, especially the operation of the circulatory system and various glands. Chapter 29, "The Retrograde Motions of the Absorbent Vessels," is Erasmus Darwin's translation of his late son Charles Darwin's dissertation. These anatomical chapters are followed by four chapters on diseases, which draws on his classification of four types of motion to identify four types of diseases: those of irritation, of sensation, of volition, and of association. Two chapters, "Of the Oxygenation of the Blood in the Lungs and Placenta" and "Of Generation" develop his theories about human reproduction, including observations related to evolution. The final chapter in the first volume is a reprint of a paper by another of Erasmus Darwin's sons, Robert Darwin, about ocular spectra. The second volume, published in 1796, is focused on classifying diseases into classes, orders, and genera. The book is divided into four major sections, based on his four classes of disease: diseases of irritation, sensation, volition, and association.