Of eggs and sperms and misunderstood worms

I’ve been reading quite a few popular science and narrative history books lately, with some rewarding results. A while ago I finished Matthew Cobb’s very engrossing The Egg & Sperm Race, about the 16th and 17th century European biologists who gradually unraveled the secrets of birth, including facts about sexual organs and reproduction that we today take for granted.

It isn’t easy to relive and then recreate the worlds inhabited by people who existed four hundred years ago, and I was amused by Cobb’s own approach to understanding his characters: he states that he tried to picture them by imagining which Hollywood actor would portray them best. (Cary Grant gets a prominent role, which automatically gave this book a gold star in my book, even before I had reached the Prologue.) But that lightweight remark aside, The Egg & Sperm Race really does make a dense subject interesting for the layperson, bringing alive such figures as Francesco Redi (whose careful experiments with putrefying matter showed that insects were bred from other, similar-looking insects – now there’s an idea!), Athanasius Kircher (an earnest but very credulous man who wrote carefully detailed books describing mythical beast and subterranean humans), Reinier de Graaf and Jan Swammerdam (who made pioneering contributions to the understanding of the human egg, though they also spent much time bickering with each other over who discovered what first). Their stories add up to a narrative comparable to that of a sharply plotted thriller. The passage where a Dutch draper named Antoni Leeuwenhoek uses his microscope to examine his own semen (less than “six beats of the pulse” after ejaculation), and discovers “a vast number of living animalcules...moving about with a snake-like motion of the tail”, reads like a mystery heading towards its resolution, even though the present-day reader knows beforehand what he’s going to see.

With the benefit of hindsight, some of the hypotheses made by these men, and some of their experiments, seem ludicrous. They were often badly mistaken on important matters, and in some cases the mistakes created scientific bottlenecks that took decades or even centuries to clear. But one shouldn’t underestimate their achievements: they worked in the face of enormous odds, including primitive technology, theological opposition, widespread superstition and misunderstanding. To put this in context, consider that even the most brilliant thinkers of the time genuinely believed that insects, and some small animals, came into being through “spontaneous generation”. There were proposed “recipes” for creating toads (they could be fashioned from the corpses of ducks placed on a dung heap!) and snakes (put a woman’s hair in a damp but sunny place). In an earlier age, even Leonardo da Vinci – a genius with a very scientific bent of mind, known for conducting dissections of cadavers – thought that semen originated in the male brain and traveled via the spinal cord, and that there was a vessel linking a woman’s nipples to her uterus (da Vinci's depiction of copulation is on the left: "I expose to men the origin of their first, and perhaps second, reason for existing," he wrote on the side of the drawing in his mirror script).

Reading The Egg & Sperm Race, it occurred to me that there’s often a big gap between the psychological acuity of the great fiction writers of yore and the relative underdevelopment of human knowledge in their era. Here’s an example. William Shakespeare is rightly considered one of the finest chroniclers of the human condition, a writer with extraordinary insight into the hearts and minds of men; his words still call out to us across the centuries, giving us a language to express complex thoughts in. Yet, from the perspective of scientific understanding, the world was a relatively backward place during Shakespeare’s lifetime, as many of the anecdotes in Cobb’s book make plain. When I think of the lines “Your worm is your only emperor for diet. We fat all creatures else to fat us, and we fat ourselves for maggots”, what now strikes me is that the playwright who wrote it had absolutely no idea where worms came from; if he ever gave the matter a thought, he probably believed – like everyone else in his time – that they simply grew out of mud-heaps!

But it’s equally true that great writers, by virtue of intuitive, unschooled wisdom, can sometimes provide cues for subsequent generations of thinkers. There’s a wonderful anecdote in The Egg & Sperm Race where a biologist derives inspiration from an episode in Homer’s Iliad – the passage where Achilles voices his fear that flies would breed worms in the wounds of the dead Patrocles. Homer’s lines, written over 2,500 years earlier, seemed to contradict the conventional wisdom that new flies simply “arose” from decaying matter, but the spark they lit in the scientist's mind indirectly hastened an important discovery. It’s an example of a brief meeting of minds between classical poetry and modern biology. Who would have thought it.

[Matthew Cobb's blog is here. Images of places/things mentioned in the book here]