When at last they were given to 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.