Ancient Views of Human Embryology
Egyptians of the Old Kingdom, approximately 3000 bc,
knew of methods for incubating birds’ eggs, but they left
no records. Akhnaton (Amenophis IV) praised the sun
god Aton as the creator of the germ in a woman, maker
of the seed in man, and giver of life to the son in the body
of his mother. The ancient Egyptians believed that the
soul entered the child at birth through the placenta.
A brief Sanskrit treatise on ancient Indian embryology
is thought to have been written in 1416 bc. This scripture
of the Hindus, called Garbha Upanishad, describes
ancient ideas concerning the embryo. It states:
From the conjugation of blood and semen (seed), the
embryo comes into existence. During the period favorable
for conception, after the sexual intercourse, (it)
becomes a Kalada (one-day-old embryo). After remaining
seven nights, it becomes a vesicle. After a fortnight it
becomes a spherical mass. After a month it becomes a
firm mass. After two months the head is formed. After
three months the limb regions appear.
Greek scholars made many important contributions to
the science of embryology. The first recorded embryologic studies are in the books of Hippocrates of Cos, the
famous Greek physician (circa 460–377 bc), who is
regarded as the father of medicine. In order to understand
how the human embryo develops, he recommended:
Take twenty or more eggs and let them be incubated by
two or more hens. Then each day from the second to that
of hatching, remove an egg, break it, and examine it. You
will find exactly as I say, for the nature of the bird can
be likened to that of man.
Aristotle of Stagira (circa 384–322 bc), a Greek philosopher
and scientist, wrote a treatise on embryology
in which he described development of the chick and
other embryos. Aristotle promoted the idea that the
embryo developed from a formless mass, which he
described as a “less fully concocted seed with a nutritive
soul and all bodily parts.” This embryo, he thought,
arose from menstrual blood after activation by male
semen.
Claudius Galen (circa 130–201 ad), a Greek physician
and medical scientist in Rome, wrote a book, On
the Formation of the Foetus, in which he described
the development and nutrition of fetuses and the structures
that we now call the allantois, amnion, and
placenta.
The Talmud contains references to the formation of
the embryo. The Jewish physician Samuel-el-Yehudi, who
lived during the second century ad, described six stages
in the formation of the embryo from a “formless, rolled-up
thing” to a “child whose months have been completed.”
Talmud scholars believed that the bones and tendons, the
nails, the marrow in the head, and the white of the eyes,
were derived from the father, “who sows the white,” but
the skin, flesh, blood, hair were derived from the mother,
“who sows the red.” These views were according to the
teachings of both Aristotle and Galen.
Embryology in the Middle Ages
The growth of science was slow during the medieval
period and few high points of embryologic investigation
undertaken during this time are known to us. It is cited
in the Quran (seventh century ad), the Holy Book of
islam, that human beings are produced from a mixture
of secretions from the male and female. Several references
are made to the creation of a human being from a nutfa
(small drop). It also states that the resulting organism
settles in the womb like a seed, 6 days after its beginning.
Reference is also made to the leech-like appearance of the
early embryo. Later the embryo is said to resemble a
“chewed substance.”
Constantinus Africanus of Salerno (circa 1020–1087
ad) wrote a concise treatise entitled De Humana Natura.
Africanus described the composition and sequential
development of the embryo in relation to the planets and
each month during pregnancy, a concept unknown in
antiquity. Medieval scholars hardly deviated from the
theory of Aristotle, which stated that the embryo was
derived from menstrual blood and semen. Because of a
lack of knowledge, drawings of the fetus in the uterus
often showed a fully developed infant frolicking in the womb
