Two matters, then, are of vital importance in language, -the forms of words, and the relations of words.
The science which treats of these two matters is called grammar.
Inflection is a change in the form of a word indicating some change in its meaning.
The relation in which a word stands to other words in the sentence is called its construction.
Grammar is the science which treats of the forms and the constructions of words.
Syntax is that department of grammar which treats of the constructions of words.
Good style is not a necessary result of grammatical correctness, but without such correctness it is, of course, impossible.