Observation of the various stages of decomposition can help determine how long a body has been dead.
Greek physicians Herophilus (335–280 BC) and Erasistratus (c.304–c.250 BC) were among the first on record to have dissected bodies. Andreas Vesalius (1514–1564), author of De humani corporis fabrica, who was able to dispel many misconceptions by dissecting human cadavers, is regarded as the father of modern human anatomy. Indian ancient texts Sushruta Samhita (2nd century BCE) and Charaka Samhita have mentioned the dissection procedure.
The tradition of dissecting criminals was carried up into the eighteenth and nineteenth century when anatomy schools became popular in England and Scotland. Criminals who were executed for their crimes were used as the first cadavers. From the 16th century until 1832, and the passage of the Anatomy Act, in Britain the only cadavers legally available for dismemberment came from executed murderers. The demand for cadavers increased when the number of criminals being executed decreased. Since corpses were in such high demand, it became commonplace to steal bodies from graves in order to keep the market supplied.
The methods of preserving cadavers have changed over the last 200 years. At that time, cadavers had to be used immediately because there were no adequate methods to keep the body from quickly decaying. Preservation was needed in order to carry out classes and lessons about the human body. Glutaraldehyde was the first main chemical used for embalming and preserving the body although it leaves a yellow stain in the tissues, which can interfere with observation and research.