John Hunter (1728-1793)
Does not the natural gradation of animals, from one to another, lead to the original species? And does not that mode of investigation gradually lead to the knowledge of that species? Are we not led on to the wolf by the gradual affinity of different varieties in the dog? (Hunter, Essays and Observations, pg.37)
John Hunter, although best known for his pioneering work in medical surgery and anatomy (also for the unsavory tactics he employed to procure bodies for dissection), has been viewed by some as an early evolutionist (e.g., Qvist, 1981 and Moore, 2005). Although many of Hunter’s observations are not inconsistent with an evolutionary worldview, it is difficult to reconcile his writings with a belief in transmutation. Regrettably, many of Hunter’s personal papers were ultimately destroyed by his brother-in-law Everard Home. Additionally, those passages that have been cited as evidence of Hunter’s evolutionary leanings were not published until long after Hunter’s death, and indeed not until after Darwin’s On the Origin of Species.
In his role as the Hunterian professor and later conservator of the Hunterian museum, Richard Owen, the comparative anatomist and later rival of Darwin (and his evolutionary theories), was tasked with editing and organizing some of Hunter’s writings, including Essays and Observations on Natural History, Anatomy, Physiology, Psychology, and Geology (1861). Of particular interest are a few passages in Essays and Observations on Natural History, Anatomy, Physiology, Psychology, and Geology published in 1861 under a section entitled “On the Origin of Species.” Here, Owen added a footnote that “the best attempt to answer” the species questions (seemingly) raised by Hunter “have been made by Charles Darwin.” However, this section heading was likely an addition made by Owen in the wake of the publication of On the Origin of Species. Whether this represents an attempt to irritate Darwin can only be guessed at.
The text which follows – when examined in the context of Hunter’s larger body of work – does not provide evidence that Hunter was thinking about the origin of (new) species. Rather, here Hunter speculates on the production of domesticated varieties from original wild species, a topic that he first took up in an 1787 paper “Observations tending to show that the wolf, jackal, and dog are all of the same species” and later in Observations on the Animal Oeconomy (1792). Hunter recognized that “if it [variation] be gradual, we should then be able to trace most varieties up to their original [wild species]” (38, Essays and Observations).
Hunter’s interest in anatomy drove him to transform his London home into a menagerie of exotic animals – especially those with any type of phenotypic abnormality – and preserved anatomical specimens. A lifetime of dissecting “monstrous” animals and observing morphological deviations from the norm led him to conclude in 1780 that “every species has a disposition to deviate from Nature in a manner peculiar to itself” (“An Account of an Extraordinary Pheasant”, The Works, vol. 4, pg. 44). In a paper for the Royal Society “On the Colour of the Pigmentum of the Eye,” Hunter drew attention to the variation that occurs in animals under domestication, and clearly proposed that variations within individuals of a species could, by an unknown “hereditary principle,” establish permanent changes, even by the work of nature alone.
The potential for hereditary variation within a species, coupled with Hunter’s clear acknowledgement of the permanence of species is best summed up in his own words: “The propagation of continuance of animals in their distinct classes is an established law of Nature, and in a general way is preserved with a tolerable degree of uniformity; but in the individuals of each species varieties are everyday produced in colour, shape, size, and disposition. Some of these changes are permanent with respect to the propagation of the animal, becoming so far a part of its nature as to be continued in the offspring.” (1792, Observations on Certain Parts of the Animal Oeconomy).