Who is applied to persons, that is, to animals distinguished by rationality, or represented as possessing it.
“The man who has no music in himself.”—Shakspeare.
The antecedent man, being a person, is followed by who.
“A stag, who came to drink at a river, seeing his own image in the clear stream, said thus to himself.”
Here the stag is represented as possessing reason and speech, and therefore the pronoun who is employed. In mythological writings in general, such as the Fables of Æsop, inferior animals are very properly denoted by the personal relative.
Which is applied to things inanimate, and creatures either devoid of all indications of rationality, or represented as such. “The city, which Romulus built, was called Rome.” Here which is used, the word city being the antecedent, to which it refers.
“The sloth, which is a creature remarkable for inactivity, lives on leaves and the flowers of trees.” Here the sloth, an animal hardly possessing sensation or life, is expressed by which.
The rule here given for the use of these pronouns is not uniformly observed, several good writers occasionally applying them indifferently to inferior animals, without any determinate principle of discrimination. It would be better, however, were this rule universally followed; and if such modes of expression as “frequented by that fowl, whom nature has taught,” were entirely repudiated.
Priestley, whose doctrine on this subject seems nearly to coincide with ours, has even objected to the application of the pronoun who to children, because this pronoun conveys an idea of persons possessing reason and reflection, of which mere children are incapable. He, therefore, disapproves of Cadogan’s phraseology, when he says, “a child who.”
That is applied indiscriminately to things animate and inanimate, and admits no variation.