Interjections deserve no attention.  They form no part of language, but may be used by beasts and birds as well as by men.  They are indistinct utterances of emotions, which come not within the range of human speech.

FOOTNOTES: 

[1] The reader is referred to “The Red Book,” by William Bearcroft,
     revised by Daniel H. Barnes, late of the New-York High School, as a
     correct system of teaching practical orthography.

[2] Gall, Spurzheim, and Combe, have reflected a light upon the science
     of the mind, which cannot fail of beneficial results.  Tho the
     doctrines of phrenology, as now taught, may prove false—­which is
     quite doubtful—­or receive extensive modifications, yet the
     consequences to the philosophy of the mind will be vastly useful. 
     The very terms employed to express the faculties and affections of
     the mind, are so definite and clear, that phrenology will long
     deserve peculiar regard, if for no other reason than for the
     introduction of a vocabulary, from which may be selected words for
     the communication of ideas upon intellectual subjects.

[3] Metaphysics originally signified the science of the causes and
     principles of all things.  Afterwards it was confined to the
     philosophy of the mind.  In our times it has obtained still another
     meaning.  Metaphysicians became so abstruse, bewildered, and lost,
     that nobody could understand them; and hence, metaphysical is now
     applied to whatever is abstruse, doubtful, and unintelligible.  If a
     speaker is not understood, it is because he is too metaphysical. 
     “How did you like the sermon, yesterday?” “Tolerably well; but he
     was too metaphysical for common hearers.”  They could not understand
     him.

[4] In this respect, many foreign languages possess a great advantage
     over ours.  They can augment or diminish the same word to increase
     or lessen the meaning.  For instance; in the Spanish, we can say
     Hombre, a man; Hombron, a large man; Hombrecito, a young
     man, or youth; Hombrecillo, a miserable little man; Pagaro, a
     bird; Pagarito, a pretty little bird; Perro, a dog;
     Perrillo, an ugly little dog; Perrazo, a large dog.

The Indian languages admit of diminutives in a similar way.  In the Delaware dialect, they are formed by the suffix tit, in the class of animate nouns; but by es, to the inanimate; as, Senno, a man; Sennotit, a little man; Wikwam, a house; Wikwames, a small house.—­Enc.  Amer.  Art.  Indian Languages, vol. 6, p. 586.

[5] Mr. Harris, in his “Hermes,” says, “A preposition is a part of
     speech, devoid itself of signification; but so formed as to unite
     two words that are significant, and that refuse to coalesce or
     unite themselves.”