Editing Embryology (section)

====Hippocrates====
Some of the most well-known early ideas on embryology come from [[Hippocrates]] and the [[Hippocratic Corpus]], where discussion on the embryo is usually given in the context of discussing [[obstetrics]] (pregnancy and childbirth). Some of the most relevant Hippocratic texts on embryology include the ''Regimen on Acute Diseases'', ''On Semen'', and ''On the Development of the Child''. Hippocrates claimed that the development of the embryo is put into motion by fire and that nourishment comes from food and breath introduced into the mother. An outer layer of the embryo solidifies, and the fire within consumes humidity which makes way for development of bone and nerve. The fire in the innermost part becomes the belly and air channels are developed in order to route nourishment to it. The enclosed fire also helps form veins and allows for circulation. In this description, Hippocrates aims at describing the causes of development rather than describing what develops. Hippocrates also develops views similar to [[preformationism]], where he claims that all parts of the embryo simultaneously develop. Hippocrates also believed that maternal blood nourishes the embryo. This blood flows and coagulates to help form the flesh of the fetus. This idea was derived from the observation that menstrual blood ceases during pregnancy, which Hippocrates took to imply that it was being redirected to fetal development. Hippocrates also claimed that the flesh differentiates into different organs of the body, and Hippocrates saw as analogous an experiment where  a mixture of substances placed into water will differentiate into different layers. Comparing the seed to the embryo, Hippocrates further compared the stalk to the umbilical cord.<ref>Joseph Needham, ''A History of Embryology'', Cambridge 1959, pp. 31-37.</ref>