中国古典文学 has the preface.
Here's the first paragraph:
The translation of
“To one who has seen too little of the world, everything is strange.” is:
There is also an entry for this in ABC Proverbs which says:
Lit [Things (which are)] seldom seen [are felt to be] strange.
Note Cf. the preface to Chū Kè Pāi'àn Jīngqì; now more commonly said shǎo jiàn, duō guài; see also the preceding entry.
Like the definition mentions the more, modern, common variant of this phrase is 少见多怪 which ABC defines as:
The less one has seen, the more one marvels.
ABC Proverbs also contains the old phrase with an added sentence:
Lit [One who has] seen little regards many things as strange; [(s)he] sees a camel [and] calls [it a] horse with a hunchback.