早在公元一世纪，罗马学者老普林尼写道：“用大戟树汁书写，字迹可以隐形。”

As early as the first century AD , Pliny the Elder wrote that the sap of a tithymalus plant could be used to render a message invisible to prying eyes.

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早在公元一世纪，伟大的罗马学者老普林尼，收集了当时已知的，所谓在世界边缘生活的各种生物的图形。

Back in the first century, AD, Pliny the Elder, a great Roman scholar, collected descriptions of creatures who lived at the very edge of the known world.

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