The effect of alcohol on monkeys, and how it might inform human encounters within the continuum of healthy and disease states, has become a field of serious academic inquiry.
As I mentioned the other day, Darwin’s original works have been on my reading (bucket) list, and in going through them I’m impressed with a number of things about his writings. One is that he freely quotes from many other naturalists and physiologists (very liberally from the work of Sir Charles Bell on the significance of facial expressions – after whom Bell’s Palsy was named). He also provides glimpses of wry humor, evidenced in his passage concerning The Bodily Structure of Man (p. 785, From So Simple A Beginning). Darwin notes that many kinds of monkeys have a strong taste for tea, coffee, and liquors, and he has witnessed some species smoking tobacco with pleasure. Citing the work of Alfred Brehm, who studied the after-effects of strong spirits on drunken monkeys, Darwin writes:
“On the following morning they were very cross and dismal; they held their aching heads with both hands and wore a most pitiable expression: when beer or wine was offered them, they turned away with disgust, but relished the juice of lemons. An American monkey, an Ateles, after getting drunk on brandy, would never touch it again, and thus was wiser than many men.”
On a more serious note, and pertinent to vision, Darwin observed (p.1358): “When persons who ought to begin the use of convex glasses habitually strain the waning power of accommodation, an undue secretion of tears very often follows, and the retina is liable to become unduly sensitive to light.” He addressed the intimate connection of the eye and brain (p.1352), and emphatically noted that vision was the most important of all the senses (p.1392).
Last year I blogged about why functional myopia may be the prime example of an adaptive state that has bearing on evolutionary medicine. In this regard, Darwin has a prescient sentence (p.845) in his section on the ‘Effects of the increased Use and Disuse of Parts’, published in 1871: “It is familiar to every one that watchmakers and engravers are liable to become short-sighted, whiles sailors and especially savages are generally long-sighted.”
Note that Darwin isn’t saying that myopia simply pre-disposes those who possess it to gravitate toward occupations requiring intense and sustained near work. He’s stating that sustained near work requiring visual precision pre-disposes the individual to myopia. He is also quick to add that “short-sight and long-sight certainly tend to be inherited“. In this regard he acknowledged the dual nature-nurture factors framing refractive status, and anticipated the role of epigenetics.