development of the
chick (1615). Harvey, who was a pupil of Fabricius, likewise published
an account of the embryology of the chick.[10] In his philosophy and
habit of thought Harvey was a follower of Aristotle. It is worth
noting that in his _Exercitationes anatomicae de motu cordis_ (1628)
there is a passage which dimly foreshadows the law of recapitulation
in development which later had so much vogue.[11]

A stimulating contribution to comparative anatomy was made by
Belon,[12] who published in 1555 a _Histoire de la nature des Oyseaux_,
in which he showed opposite one another a skeleton of a bird and of a
mammal, giving the same names to homologous bones. The anatomy of
animals other than man was indeed not altogether neglected at this
time. Coiter (1535-1600) studied the anatomy of Vertebrates,
discovering among other things the fibrous structure of the brain.
Carlo Ruini of Bologna wrote in 1598 a book on the anatomy of the
horse.[13] Somewhat later Severino, professor at Naples, dissected many
animals and came to the conclusion that they were built upon the same
plan as man.[14] Willis, of Oxford and London, in his _Cerebri Anatome_
(1659) recognised the necessity for comparative study of the structure
of the brain. He found out that the brain of man is very like that of
other mammals, the brain of birds, on the contrary, like that of
fishes![15] He described the anatomy of the oyster and the crayfish. He
had, however, not much feeling for morphology.

The foundation of the Jardin des Plantes at Paris in 1626 and the
subsequent addition to it of a Museum of Natural History and a
menagerie gave a great impulse to the study of comparative anatomy by
supplying a rich material for dissection. Advantage was taken of these
facilities, particularly by Claude Perrault and Duverney.[16] In a
volume entitled _De la Mecanique des Animaux_, Perrault recognises
clearly the idea of unity of type, and even pushes it too far, seeking
to prove that in plants there exists an arterial system and veins
provided with valves.[17]

The beginning of the 17th century saw the invention of the microscope,
which was to have such an enormous influence upon the development of
biological studies. It did not come into scientific use until well on
in the middle of the century. Just before it came into use Francis
Glisson (1597-1677), an Englishman, gave in the introduction to his
treatise on the liver an account of the notions then current o