Meaning of the phrase "treats of" in the title of chapter 1 of Oliver Twist [closed]

The title of chapter 1 of Oliver Twist is as follow:

"Treats of the place where Oliver Twist was born...".

What is the exact meaning of the plural word "treats"? I assume it means something like "argumentation" however I have not been able to find the exact word (in plural form) in any dictionary. Is it an archaic word? Thanks for the help.

It's not in plural form because it has an added s which is only done with verbs in the 3rd person singular:

I treat, you treat, he/she/it treats, we treat, you treat, they treat.

And from there it reduces down a general reference as we just have to look up treat:

To discourse on; to represent or deal with in a particular way, in writing or speaking

Being a subtitle, the omitted subject is the work itself. So it's equivalent to "This chapter treats of the…".

'Treats of' means 'explains' or 'describes'. It's archaic now.

treat

VERB [with object]

1.2 Present or discuss (a subject)

Oxford Dictionaries. Oxford University Press, n.d. Web. 09 January 2015.