through an intermediate stage."

Professor R.A. Cooley of Montana, from whose report the above quotation
is taken, has also made studies of the habits of the tick and believes
there can be no doubt that it is the disseminator of the disease.

_Relapsing Fever._ The relapsing fever is an infectious disease or
possibly a group of closely related infectious diseases occurring in
various parts of the world. Occasionally it is introduced into America,
but it does not seem to spread here. It has been shown that the disease
is communicated from one person to another by means of blood-sucking
insects. In Central Africa where the disease is very prevalent a certain
common tick (_Ornithodoros moubata_) (Fig. 18) is known to transmit the
disease. This tick lives in the resting places and around the huts of
the natives and has habits very similar to the bedbug of other climes,
feeding at night and hiding during the day. It attacks both man and
beast and is one of the most dreaded of all the African pests.

Nathan Bank, our foremost authority on ticks, in summing up the evidence
against them says:

"It is therefore evident that all ticks are potentially dangerous.
Any tick now commonly infesting some wild animal, may, as its
natural host becomes more uncommon, attach itself to some domestic
animal. Since most of the hosts of ticks have some blood-parasites,
the ticks by changing the host may transplant the blood-parasites
into the new host producing, under suitable conditions, some
disease. Numerous investigators throughout the world are studying
this phase of tick-life, and many discoveries will doubtless
signalize the coming years."

MITES

The mites are closely related to the ticks, and although none of them
has yet been shown to be responsible for the spread of any disease their
habits are such that it would be entirely possible for some to transmit
certain diseases from one host to another, from animal to animal, from
animal to man, or from man to man. A number of these mites produce
certain serious diseases among various domestic animals and a few are
responsible for certain diseases of men.

_Face-mites._ Living in the sweat-glands at the roots of hairs and in
diseased follicles in the skin of man and some domestic animals are
curious little parasites that look as much like worms as mites (Fig.
19). Such diseased follicles become filled with fatty matter, the upper
end b