John's hand trembles.

John's is a noun, [because it is] the name of a person—proper, the name of an individual—masculine gender, it denotes a male—third person, spoken of—singular number, it implies but one—and in the possessive case, it denotes possession—it is governed by the noun "hand," according to

RULE 12. A noun or pronoun in the possessive case, is governed by the noun it possesses.

Declined—Sing. nom. John, poss. John's, obj. John. Plural—nom. Johns, poss. Johns', obj. Johns.

Hand is a noun, the name of a thing—common, the name of a sort or species of things—neuter gender, it denotes a thing without sex—third person, spoken of—sing. number, it implies but one—and in the nominative case, it is the actor and subject of the verb "trembles," and governs it agreeably to

RULE 3. The nominative case governs the verb:—that is, the nominative determines the number and person of the verb.

Declined—Sing. nom. hand, poss. hand's, obj. hand. Plur. nom. hands, poss. hands', obj. hands.

Trembles is a verb, a word which signifies to do—active, it expresses action—third person, singular number, because the nominative "hand" is with which it agrees, according to

RULE 4. The verb must agree with its nominative in number and person.