ds, and how do
they come to produce such serious disturbances? This can be partially
answered by saying that they are tonsils and with all a tonsil's
susceptibility to irritation and inflammation. But that only raises the
further question, What is a tonsil? And to that no answer can be given
but Echo's. They are one of the conundrums of physiology. All we know of
them is that they are not true _glands_, as they have neither duct nor
secretion, but masses of simple embryonic tissue called _lymphoid_,
which has a habit of grouping itself about the openings of disused
canals. This is what accounts for their position in the throat, as they
have no known useful function. The two largest, or throat-tonsils,
surround the inner openings of the second gill-slits of the embryo; the
lingual tonsil, at the base of the tongue below, encircles the mouth of
the duct of the thyroid gland (the _goitre_ gland); and our own
particular Pandora's Box above, in the roof of the pharynx, is grouped
about the opening of another disused canal, which performs the singular
and apparently most uncalled-for office of connecting the cavity of the
brain with the throat. They can all of them be removed completely
without any injury to the general health, and they all tend to shrink
and become smaller--in the case of the topmost, or pharyngeal, almost
disappear--after the twelfth or fourteenth year.

Not only have they an abundant crop of troubles of their own, as most of
us can testify from painful experience, but they serve as a port of
entry for the germs of many serious diseases, such as tuberculosis,
rheumatism, diphtheria, and possibly scarlet fever. They appear to be a
strange sort of survival or remnant,--not even suitable for the
bargain-counter,--a hereditary leisure class in the modern democracy of
the body, a fertile soil for all sorts of trouble.

Here, then, we have this little bunch of idle tissue, about the size of
a small hazelnut, ready for any mischief which our Satan-bacilli may
find for its hands to do. A child kept in a badly ventilated room
inhales into his nostrils irritating dust or gases, or, more commonly
yet, the floating germs of some one or more of those dozen mild
infections which we term "a common cold." Instantly irritation and
swelling are set up in the exquisitely elastic tissues of the nostrils,
thick, sticky mucous, instead of the normal watery secretion, is poured
out, the child begins to sneeze and snuffle and "ru