functional importance to them, as it can be rapidly drawn across the whole
eye-ball. It is found in some reptiles and amphibians, and in certain
fishes, as in sharks. It is fairly well developed in the two lower
divisions of the mammalian series, namely, in the monotremata and
marsupials, and in some few of the higher mammals, as in the walrus. But
in man, the quadrumana, and most other mammals, it exists, as is admitted
by all anatomists, as a mere rudiment, called the semilunar fold. (35.
Muller's 'Elements of Physiology,' Eng. translat. 1842, vol. ii. p. 1117.
Owen, 'Anatomy of Vertebrates,' vol. iii. p. 260; ibid. on the Walrus,
'Proceedings of the Zoological Society,' November 8, 1854. See also R.
Knox, 'Great Artists and Anatomists,' p. 106. This rudiment apparently is
somewhat larger in Negroes and Australians than in Europeans, see Carl
Vogt, 'Lectures on Man,' Eng. translat. p. 129.)

The sense of smell is of the highest importance to the greater number of
mammals--to some, as the ruminants, in warning them of danger; to others,
as the Carnivora, in finding their prey; to others, again, as the wild
boar, for both purposes combined. But the sense of smell is of extremely
slight service, if any, even to the dark coloured races of men, in whom it
is much more highly developed than in the white and civilised races. (36.
The account given by Humboldt of the power of smell possessed by the
natives of South America is well known, and has been confirmed by others.
M. Houzeau ('Etudes sur les Facultes Mentales,' etc., tom. i. 1872, p. 91)
asserts that he repeatedly made experiments, and proved that Negroes and
Indians could recognise persons in the dark by their odour. Dr. W. Ogle
has made some curious observations on the connection between the power of
smell and the colouring matter of the mucous membrane of the olfactory
region as well as of the skin of the body. I have, therefore, spoken in
the text of the dark-coloured races having a finer sense of smell than the
white races. See his paper, 'Medico-Chirurgical Transactions,' London,