Sentence:  There are certain Climates, where the Mind ripens and attains ſooner to Perfection than in others: nay there are ſome Conſtitutions of Body, where the humours are ſo exactly mixt, that they form an admirable Temper; the Effects thereof are diſcoverable in the firſt <WSD>"Juvenile</WSD>" Years, and leave very fine Remains, even in a decrepit Age. 
Meaning of the word marked with <WSD> tags:  Young; not fully developed.