折疑論 2.18

2.18

探枳棘之巢。求鸞鳳之卵（橘逾淮北而為枳棘者。棘鍼也。如枳棘上之鳥巢。欲探取鸞鳳之卵。不亦難乎）。

or searches the nests in thornbushes seeking the eggs of phoenixes, (When the orange tree crosses north of the Huai River, it becomes the trifoliate orange [zhi]; ji refers to sharp brambles. To search a bird's nest in a thornbush seeking the egg of a phoenix—would that not be difficult?)