信封,既是通信双方姓名、地址的载体,又是彼此心声交流的掩体。那么,在信封问世前,人们是如何为信件保密的呢?说来有趣,也挺残酷。最初,有人竟借用头发充作信封。古希腊奴隶主写信前,先将一名奴隶的头发剃光,然后,在头皮上写好信。不过,这封信得等到新的头发长出来足以遮盖住“信”后,才能被这名奴隶送往收信人那儿。收信人只需把那些长出来的头发再剃掉,信也就一览无余了。 Envelopes, both the name and address of communication carriers, but also exchange of ideas between the bunkers. So, how did people keep their letters confidential before they came out? It was fun and cruel. At first, someone borrowed hair as an envelope. Ancient Greek slaves before the letter, first a slave shaved hair, and then, write a letter on the scalp. However, this letter will not be sent by the slave to the recipient until the new hair grows enough to cover the letter. The recipient simply shaves off the longer hair and the letter is glanced over.