“No point or pause-mark is admissible between the subject or nominative and the predicate, . . . .”
The “Practical Grammar,” by S. W. Clark, A.M., published by A. S. Barnes & Co., New York, gives the following rule: {p78}
“A phrase or sentence used as the subject of a verb, requires a comma between it and the verb.”
Of course the examples under the rule exhibit a corresponding difference.
“To be totally indifferent to praise or censure is a real defect in character.”—Wilson.
“To do good to others, constitutes an important object of existence.”—Clark.
Ingersoll’s Grammar (Portland, 1828) and Kerl’s—which last is now very extensively used—agree with Clark. Both have the same example as Wilson, but pointed as follows:—
“To be totally indifferent to praise or censure, is a real defect in character.”
Goold Brown (Grammar of Grammars) inserts the comma. Cobbett’s Grammar omits it.
Take up the first dozen books that come to hand, and you will find diversity of practice.