So in this latest entry, Lucy starts getting blood transfusions—first from Arthur, then from Seward and Van Helsing as well.
Dracula was published in 1897; the ABO blood groups were discovered a mere 4 years later, in 1901.
What's the smallest gap you know of between a plot point appearing in a novel and a scientific discovery that renders it implausible?
In Adrian Tchaikovsky's Children of Time (published June 2015), which famously features UpliftedPortia jumping spiders, a minor plot point turns on their inability to hear. In October 2016, researchers discovered that jumping spiders can hear (news article), and since then hearing has been discovered in many other families of spiders.
Can anyone beat this?
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All the transfusions are successful. The riskiness of blood transfusions, well known by then, is never mentioned. However, it's portrayed as a last-resort emergency measure where the risk of Lucy dying is far greater if she doesn't get a transfusion. This is another example of the novel stretching the bounds of known science/technology for artistic licence (the phonograph, which Seward uses for often long audio recordings, was less than a decade old and the cylinders could only record a few minutes' worth).
