three of the author's foot-notes have been omitted.]

[Footnote 58: "The American Beaver and his Works," 1868.--Author's
note.]

[Footnote 59: All the following statements, given on the authority of
these two naturalists, are taken from Rengger's "Naturgesch. der
Säugethiere von Paraguay," 1830, s. 41-57, and from Brehm's
"Thierleben," B.i. s. 10-87.--Author's note.]

[Footnote 60: A critic, without any grounds ("Quarterly Review," July,
1871, p. 72), disputes the possibility of this act as described by
Brehm, for the sake of discrediting my work. Therefore I tried, and
found that I could readily seize with my own teeth the sharp little
claws of a kitten nearly five weeks old.--Author's note.]




THE IMPORTANCE OF DUST: A SOURCE OF BEAUTY AND ESSENTIAL TO LIFE[61]

ALFRED RUSSEL WALLACE


The majority of persons, if asked what were the uses of dust, would
reply that they did not know it had any, but they were sure it was a
great nuisance. It is true that dust, in our towns and in our houses, is
often not only a nuisance but a serious source of disease: while in many
countries it produces ophthalmia, often resulting in total blindness.
Dust, however, as it is usually perceived by us, is, like dirt, only