《论衡·卷三·本性篇》
其注释说： 比喻像白色的丝，用青色的染料去染它就成为青色，用红色的染料去染它就成为红色。 
其传曰： 譬犹练丝，染之蓝则青，染之硃则赤。 
Its annotation states: This is a metaphor, like a white silk that turns green when dyed with green dye, and red when dyed with red dye.