Lifting Titan ’ s Veil : Exploring the Giant

anatomist. The project was so complex that Sabin spent seven weeks with Ziegler working on the models. It is clear from Sabin’s letters home that the process of modeling illuminated her understanding of the threedimensional of the brain. These, and almost all of the models were associated with publications in learned journals, lending scientific authority to what might have been considered merely a commercial venture. Ziegler was a physician and considered himself a part of the academic community rather than an artisan who made his living making models. Indeed, he was rewarded with an honorary degree from the University of Freiburg. Hopwood describes Gustav Born’s method of making models that translated serial sections of embryos into serial slices of wax that could be assembled to make a whole, which reduced the amount of subjective interpretation required and made the process more mechanical. Interestingly, a similar process was followed by the early protein crystallographers who traced the electron density maps onto clear sheets of plastic, which were then stacked on one another. It is unfortunate that Hopwood’s writing is not always as stylish as the images in the book and some sentence constructions are hardly felicitous; for example, ‘Ziegler had a certain status, then, though perhaps no better than as a drawing teacher he would have enjoyed...’ or ‘With a new generation of modellers in place, it is here that in the next chapter we return’. The Whipple Museum in Cambridge has produced a very attractive book but it is a pity that the size of the font is rather smaller than older readers will like, and it is regrettable that there is not an index. On the other hand, using the footnotes is much easier than usual because they are numbered consecutively through the book, rather than chapter by chapter. Hopwood discusses the decline of the models – how there was a move away from detailed morphological studies of developing embryos. This became ever more pronounced as embryologists transformed into developmental biologists and adopted many of the powerful new approaches being used in molecular genetics and cell biology. Yet morphology continues to be a key element of development – how could it be otherwise when the structural changes realized by an embryo are the bedrock of the developmental process? Today, the colored waxes of the Zieglers’ models are fluorochromes lighting up the three-dimensional patterns of gene expression or protein distribution; there are websites with three-dimensional representations of embryos that can be rotated. And yet, for all their realism, these images on a monitor cannot compare with the glories of the Zieglers’ work. My next visit to Cambridge will include a detour to the Department of Anatomy to see some of the models in real life.