a. Parenthetical words can be omitted without destroying the sense. See examples under Rule IV.
b. Parenthetical expressions obstruct the flow of the sentence, but can not be omitted without either destroying the sense, or changing the meaning intended to be conveyed. See examples given above.
2. When parenthetical expressions are short, or closely connected with the rest of the sentence, it is better to omit punctuation marks.
3. Writers differ very much in omitting or using commas in parenthetical expressions. It is sometimes immaterial whether punctuation marks are used or not, but, in many cases, there are few rules so well adapted to bring out the meaning of the writer.
Rule VI. Inverted Expressions.—Expressions which are not in their natural order, are frequently separated from the rest of the sentence by a comma.
EXAMPLES.
“In everything that relates to science, I am a whole Encyclopædia behind the rest of the world.”—Lamb.
“In all unhappy marriages I have seen, the great cause of evil has proceeded from slight occasions.”—Steele.
REMARKS.