Sentence:  I say this much of this action, that it is requisite we should remit the same unto certaine prescribed night-houres, and by custome (as I have done) force and subject our selves unto it; But not (as I have done), growing in yeeres, strictly tie himselfe to the care of a particular convenient place, and of a commodious <WSD>"Ajax</WSD>" or easie close-stoole for that purpose, and make it troublesome with long sitting and nice observation. 
Meaning of the word marked with <WSD> tags:  A toilet.