The driving force behind scientific innovation is a belief, a kind of religion that you have discovered the hand of God that formed you. Science is not as clinical as we think it is. The history of science is full of folklore seeping into science, where we are governed by beliefs rather than observation.

Before we knew about hormones and the field of endocrinology, we knew about testicles. John Hunter (1728–1793) performed testicular transplantation from a cock into the abdominal cavity of a hen. In 1849, Arnold Berthold (1801–1863) linked the physiological and behavioural changes of castration to a substance secreted by the testes. We knew that there was something in the testicles that affected us.

When at the age of 72, Charles Edouard Brown-Séquard (1817-1894) reported dramatic rejuvenating effects after injecting himself with an elixir – a mixture of pounded dog and guinea-pig testicles, mixed with some semen and blood – he was expressing a long-held belief that testicles are important for staying young.

As a renowned surgeon, he quickly lost favour with the establishment. But the search for rejuvenation continued. Following in Séquard’s footsteps, Serge Voronoff (1866-1951), tried this concoction on himself. As we now know, this concoction had too little testosterone to have any effect, and Voronoff similarly found this concoction to be useless. But not deterred, Voronoff went one step further.

Being a student of Alexis Carrel, the Nobel Prize winner in Medicine, Voronoff was adapt at organ transplantation. He decided to use his newly acquired skill of transplantation and surgically implant slivers of monkey testicles into the scrotum of humans.

He used monkeys because he saw how virile and strong they were. Results showed a dramatic effect. Publishing before/after pictures in esteemed journals of Lancet and Scientific American, Voronoff was able to show dramatic positive outcomes.

By the Great Depression of the 1930s, over 500 men had received Voronoff’s monkey balls therapy. And it was not just rejuvenation that was achieved.

Voronoff reported that sex drive was improved, better memory, the ability to work longer hours, better eyesight and prolonging life. And as if that was not enough, the great surgeon speculated that monkey balls therapy might be beneficial for people with ‘dementia praecox’ (premature dementia), which was renamed by Emil Kraepelin, the father of Alzheimer’s disease, as schizophrenia. It was no surprise therefore that this wonder therapy become so popular. In order to cope with the increasing demands, Voronoff set up his own monkey balls farm on the Italian Riviera.

Experimentation, despite its reliance on belief, is how we learn about our amazing ageing body

Unfortunately, Voronoff’s medical competency was marred by his association with the infamous American charlatan John Richard Brinkley (1885–1942). Without a medical degree, but with a lot of business acumen, Brinkley transplanted goat testicles into humans. He used goats because they appeared so virile.

Operating a multitude of clinics and hospitals in several states, Brinkley promoted this procedure as a cure for a wide range of male ailments. In 1938, Morris Fishbein, the editor of the Journal of the American Medical Association and well known at the time as a debunker of quack medicine, attacked Brinkley by publishing a two-part series called Modern Medical Charlatans. Brinkley took Fishbein to court for defamation and lost.

There were other more recent examples attacking the testicles for the sake of rejuvenation. Overlapping some of Voronoff’s success, by 1918 Eugen Steinach (1861–1944) started performing the first vasectomy on humans for rejuvenation. Although sterilisation, by cutting the pipe from the testicles, had been around for some time – used on prisoners and mentally deficient people – by the turn of the 20th century this was used to rejuvenate old men.

Most notable patients included Sigmund Freud and Nobel Prize winner poet William Butler Yeats. To this day, vasectomy does not seem to have any effect (good or bad) on health. The peak of transplantation of testicles came with Paul Niehans (1882–1971), who claimed to have performed more than 50,000 “cellular therapy” treatments.

Niehans’ 1960 book Introduction to Cellular Therapy, working on testicular secretions, again proved popular. He boasted patients who included Pope Pius XII, Bernard Baruch and Aristotle Onassis.

In 1935, the Dutch Kàroly Gyula David and his colleagues identified the critical ingredient in testicles, testosterone. In 2010 the Spanish physician M. Mercè Fernández-Balsells and her colleagues published a review of 51 studies of testosterone on older men. Although they reported changes in blood composition, they reported no significant effect on mortality, prostate or cardiovascular outcomes.

While earlier reviews reported negative prostate and cardiovascular events, ongoing science is still too vague to ascertain any causality. We might joke about this, but the experimentation of these pioneers resulted in the creation of the new study of endocrinology – the study of chemicals produced by organs transported by blood all over the body.

The secret chemical that everyone wanted to reproduce was testosterone. And even though some of the positive outcomes reported in these early studies have been criticised as primarily placebo, there were searching for something that was real, even though it was not rejuvenation.

And the story continues. Even with the publication of The Monkey Gland Affair in 1986 by David Hamilton, an experienced transplant surgeon, the utility of transplanting testicles from animals remains undecided. He discusses how animal tissue inserted into a human would not be absorbed, but will be instantly rejected.

At best, it would result in scar tissue, which might fool a person into believing the graft is still in place. But what we have subsequently learned is that sertoli cells that surround the testicles protect organs from being rejected. So much so that new organ transplantation techniques uses these cells to suppress the body from rejecting transplant organs.

There is still a lot to learn and although we might find humour in a lot of experimentation, they are useful in pushing the frontiers of science. With one eye on charlatans, we should keep the other eye on our future. Experimentation, despite its reliance on belief, is how we learn about our amazing ageing body.

Mario Garrett was born in Cospicua and went to St Paula Technical School before moving to England with his family. He is currently a professor of gerontology at San Diego State University in California, US.

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