《三国志·魏书·方技传》
有人对于用不同的方法很奇怪，华佗说： 儿寻是外热，李延是内热，所以治疗时应该有所不同。 
或难其异，佗曰： 寻外实，延内实，故治之宜殊。 
Some people were surprised that different methods were used, and Hua Tuo said: Ni Xun is external heat, Li Yan is internal heat, so different treatments should be used.