You can tell from the title that this is a book about metamorphosis, but it’s not quite what you might expect. This is in fact a long essay that juxtaposes the material progress of a developing scientific subject with much wider, emotionally charged issues of what constitutes proper human understanding. A sentence from the preface will give you the idea quite well: “[Metamorphosis] is not a biological textbook, or a philosophical treatise, or even a straightforward history of science, but a meditation… In a more lyrical sense, [it] is a portal into our innermost obsessions – how it’s possible that we remain the same while changing all the while… The story goes back and forth between conventional and imaginative biography, natural creatures and intellectual history, science and philosophy and art. A spirit of loose jointedness blows through the book.”
If it’s a detailed account of the current state of the science of metamorphosis that you want, then this probably isn’t the book for you. Although the author, Oren Harman, succeeds in giving the reader a good account not only of our current scientific understanding of metamorphosis (it is mostly about insects, but other animals also feature), the book is really about the to-and-fro of how scientific understanding develops. Looked at this way, the book is literally terrific, not only for the general reader, but also for those who are themselves involved in the story. The ‘loose-jointedness’ is its particular merit.
Nowadays, we rarely reflect on what an extraordinary phenomenon animal transformation is; the idea that a caterpillar and a butterfly are actually both the same creature does not come naturally. The journey to a proper understanding of what is going on has taken a number of serious detours. Beginning with Aristotle, the book follows ideas about metamorphosis all the way from myths and legends through to modern molecular biological models of cellular control. There are detailed accounts here of three separate stages of discovery; one might well comment that the transitions between them have required their own conceptual metamorphoses.
This is a book that is primarily about people. Some contributors to our present understanding of metamorphosis are given star billing. In the book’s first part, the seventeenth century artist and naturalist, Maria Sybilla Merian, is celebrated. Until relatively recently regarded only as an extraordinarily talented natural history artist, Merian is now also recognised not only as a serious contributor to thinking about the ecological significance of metamorphosis, but also a heroic explorer who struggled against extraordinary personal difficulties as a woman working in a man’s world. Harman gives an appropriately enthusiastic account of her work and its significance. In the second part, the book evaluates the mixed legacy of the controversial embryologist and anatomist, Ernst Haeckel. I was unsure about this; I think that the book devotes too much space on Haeckel’s ethical shortcomings, which were not directly related to his ideas about metamorphosis. On the other hand, one has to admit that Haeckel was an important figure in reaching out to the general public on this and other evolutionary and developmental biology topics. In its third part, the book provides a detailed account of the important twentieth and twenty-first century contributions of the American insect developmental biologists, Lynn Riddiford and Jim Truman (both Honorary Fellows of the Royal Entomological Society), whom Harman interviewed in person. He obviously just adores them (who wouldn’t!).
Many other insect scientists (including me!) play walk-on parts as Harman’s story progresses, but this book is not a straightforward history of how the science of metamorphosis developed; although many other star contributors such as V.B. Wigglesworth and Caroll Williams are introduced, there are plenty of key ideas that are omitted and scientists who made significant contributions but aren’t mentioned. Those involved in the science know that the journey to understanding has been long and that many signposts and milestones have had to be laboriously constructed. But on reflection, the omissions are fair enough – as the author says, this isn’t a textbook. The book’s achievement is considerable; despite the complexity of the topic, Harman clearly and accurately summarises both old and new advances in understanding the cellular control of metamorphosis, importantly successfully conveying the ‘feel’ of the present state of the art.
And Harman goes further, by looking at how metamorphosis has been seen in literature. The characters in this part of the drama include the Roman poet, Publius Ovidius Naso (Ovid), who sought to find significance in metamorphic transformations for the human condition, and extend to a whole host of thinkers and writers from Saint Thomas Aquinas to the Austro-Hungarian novelist Stefan Zweig (yes, I’m selecting alphabetically from the astonishingly well-peopled index). Just looking at the letter ‘G’, Harman manages to find room for Galen, Gandhi, King George 1st, God, Goethe and Gutenberg, as well as the scientists Walter Gehring and Stephen Jay Gould.
Are there any shortcomings? Well, perhaps. Harman’s facility for placing those he writes about in both the scientific and the cultural milieux in which they worked is impressive, but in my opinion he gives insufficient credit to those 17th century Renaissance giants of comparative anatomy, Jan Swammerdam, Marcello Malpighi and William Harvey. Between them these three really set the agenda for how our understanding of metamorphosis subsequently developed. Sometimes, Harman is simply unfair to those who thought deeply about what metamorphosis means and how it might work; for example, he grotesquely dismisses Howard Hinton simply as ‘cocksure’ – it’s true that Hinton was mistaken on the developmental origin of the pupa, but in science we all get to be wrong about something! A particular gripe is that far too much space is given in the book to an obscure and convincingly disproved 20th Century theory of the evolutionary origin of echinoderm metamorphosis in an improbable hybridisation event between marine animals from two completely different phyla. Harman is sympathetic to the theory’s originator, whom he portrays as a creative thinker, brutally dismissed by an intolerant and reactionary scientific establishment, but in my view, it would have been better if this obviously crackpot idea had not been mentioned at all. This is indeed an enjoyable and thought-provoking book about how science progresses, populated by a host of fascinating characters who are brought to life by a first-rate writer. It is mostly about insects, and I predict that every entomologist will enjoy it, but its scope is much broader than that. What Harman is really doing here is to convey the romance of actually doing science; how it feels to devote yourself to understanding natural phenomena that run contrary to the normal experience of humans, like the transformation of a maggot into a fly. What the author doesn’t actually say anywhere, however, is that the excitement of science is only in part about making discoveries; it’s also about the thrill of not knowing the answers to your questions.
