A deep dive from Salon recently explored the curious tale of Antonie van Leeuwenhoek, a Dutch amateur scientist who discovered sperm only to wish he could unsee it. You might think it odd that a person be the first to view one of the most pivotal cells in the creation of life only to ask for it to be quashed, but van Leeuwenhoek’s religious sentiments meant he was more than happy for his findings to be deleted from the record.
How van Leeuwenhoek came to be an unwilling participant in the discovery of sperm began in his hometown of Delft in the Dutch Republic during the 17th century. Here, he worked with textiles and after getting fed up of lousy lenses that were incapable of properly capturing fine threads, he decided to make his own.
He created single-lens microscopes that made his life as a draper easier, but also transformed him into arguably the world’s first microbiologist as he began using them to look at the world’s tiniest natural wonders. He looked at the plaques between his teeth that he described as “thick as if 'twere batter,” and the ciliate Vorticella whose locomotion he “found mightily diverting.”
His exploration of the microbial world took him on a journey through animal and plant tissues armed with his DIY microscope, and he reported his findings as he went. So naturally, it was only a matter of time before someone asked him to look at some sperm.
Suffice to say, van Leeuwenhoek was not taken by the idea, and his uncertainty surrounding the research’s propriety in a religious society was palpable in his communications.
"If your Lordship should consider that these observations may disgust or scandalise the learned, I earnestly beg your Lordship to regard them as private and to publish or destroy them as your Lordship sees fit,” Smithsonian reports he wrote to the Royal Society, the journal that received most of his findings.
Eventually, he agreed, but his methodology was limited by his religious beliefs meaning the only samples he was willing to gather for his research were those that came naturally during his conjugal relations. In short, he got them from his wife.
Looking at the fluid through the lens, he identified small “animalcules” and while it was technically the first discovery of sperm, he actually had no idea what he was looking at. He had described “animalcules” in samples taken from the mouths of men and women, but these miniature critters were probably bacteria which alongside protists, blood cells, nematodes, and rotifers, he was the first person to identify.
In the 17th century, the idea of gametes (sex cells) fusing to form an embryo hadn’t crossed humanity’s worried minds, and it wasn’t until much later that research into parasitic worms gave rise to the idea of spermatozoa, the fancy name for sperm. Van Leeuwenhoek’s own research went on to look at the sperm of other animals, and while suggestions were made of the animalcules’ role in “generation” (the origin of offspring), nothing concrete was made in his lifetime.
The bashful Calvinist continued his work as a draper while also tinkering with his microscopes. He might have been an unwilling contributor to the discovery of sperm, but his work constitutes a pivotal moment in our understanding of life and evolution.
Not bad for a guy who just wanted to make nice clothes.