the world as Anatomical Engravings, they showed conclusively
that Eustachius was equal, if not superior to Vesalius in his knowledge
of anatomy. It has been said of this remarkable collection of engravings
that if they had been published when they were made in the sixteenth
century, anatomy would have been advanced by at least two centuries.
But be this as it may, they certainly show that their author was a most
careful dissector and observer.

Eustachius described accurately for the first time certain structures
of the middle ear, and rediscovered the tube leading from the ear to the
throat that bears his name. He also made careful studies of the teeth
and the phenomena of first and second dentition. He was not baffled by
the minuteness of structures and where he was unable to study them
with the naked eye he used glasses for the purpose, and resorted
to macerations and injections for the study of certain complicated
structures. But while the fruit of his pen and pencil were lost for more
than a century after his death, the effects of his teachings were not;
and his two pupils, Fallopius and Columbus, are almost as well known
to-day as their illustrious teacher. Columbus (1490-1559) did much in
correcting the mistakes made in the anatomy of the bones as described by
Vesalius. He also added much to the science by giving correct accounts
of the shape and cavities of the heart, and made many other discoveries
of minor importance. Fallopius (1523-1562) added considerably to the
general knowledge of anatomy, made several discoveries in the anatomy of
the ear, and also several organs in the abdominal cavity.

At this time a most vitally important controversy was in progress as to
whether or not the veins of the bodies were supplied with valves, many
anatomists being unable to find them. Etienne had first described these
structures, and Vesalius had confirmed his observations. It would seem
as if there could be no difficulty in settling the question as to the
fact of such valves being present in the vessels, for the demonstration
is so simple that it is now made daily by medical students in all
physiological laboratories and dissecting-rooms. But many of the
great anatomists of the sixteenth century were unable to make this
demonstration, even when it had been brought to their attention by such
an authority as Vesalius. Fallopius, writing to Vesalius on the subject
in 1562, declared that he was unable to find such valves. Ot