[87r]

please the females, they would naturally employ those which were are sweet be rendered sweet to the ears of the same species; it appears that the same sound are often from owing to owing to pleasing to to widely different animals, owing to the similarity of their nervous systems in widely different animals classes, that the same sounds are pleasing to many species, as we ourselves recognise perceive in the singing of birds & even in the chirping of certain tree-frogs giving us pleasure. On the other hand, sounds produced in order to strike terror into an enemy would be naturally be rendered harsh or displeasing.

[Expression, p. 91: "When male animals utter sounds in order to please the females, they would naturally employ those which are sweet to the ears of the species; and it appears that the same sounds are often pleasing to widely different animals, owing to the similarity of their nervous systems, as we ourselves perceive in the singing of birds and even in the chirping of certain tree-frogs giving us pleasure. On the other hand, sounds produced in order to strike terror into an enemy, would naturally be harsh or displeasing."]