Under the later convention:
Original: Every human is an animal.
New subject: nonanimal.
New predicate: human.
Result: No nonanimal is human.
The original is universally affirmative; the result is universally negative. Thus quality is reversed, while the inference preserves truth.
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Contraposition: Classical Rules, Validity and the Later Convention
Under the later convention:
Original: Every human is an animal.
New subject: nonanimal.
New predicate: human.
Result: No nonanimal is human.
The original is universally affirmative; the result is universally negative. Thus quality is reversed, while the inference preserves truth.