Developments in scientific research follow improvements in apparatus – William Harvey was hampered in his observational research into reproduction by lack of equipment. The microscope was invented 17 years after his death.
William Harvey’s story is a good read! After training at Cambridge and in Italy, he fortuitously (he chose his wife well!) became royal physician to King James I and afterwards to King Charles I. Both took an interest in his investigations and his work on the human circulation, and supported his many, many dissections by providing him with deer which they had hunted down in the royal parks and forests.
He gained fame for the results of his investigations which showed that blood flowed in a continuous circulation in the mammalian body, with the heart as its pump and valves in the veins preventing back-flow. His fellow scientists generally accepted Harvey’s work, which is perhaps one of the first examples of science moving forward as a result of experimentation, rather than as a result of unproven theories. Prior to Harvey’s publication, bloodletting was all the rage amongst physicians and the medical profession, and many non-scientists continued to want to believe this way, despite Harvey’s evidence.
William Harvey and Embryology
In addition to his research into blood and the circulation, William Harvey (1578-1657) was one of the first to study embryology (the study of reproduction in its earliest stages) by observing the development of the chick in the egg. Harvey was the first to suggest that humans and other mammals reproduced via the fertilisation of an egg by sperm. It took a further two centuries before a mammalian egg was finally observed, but nonetheless Harvey’s theory won credibility during his lifetime, partly because of his fame and standing in the scientific world.
He performed many dissections of mammal embryos at various stages of formation. From these experiments Harvey was able to formulate a new theory of animal generation, emphasizing the primacy of the egg rather than sperm. Prior to Harvey’s work, it was thought that the male sperm was the primary source of new life, and that the egg was simply an empty home, provided for the sperm to develop.
Harvey was hampered in his research into embryology by a lack of a microscope, which was not invented until some 17 years after his death. With a microscope, he would have been able to substantiate many of his perfectly correct ideas.
Follow this link for more about William Harvey and embryology: https://embryo.asu.edu/pages/william-harvey-1578-1657
And this link for a brief summary about Harvey and his work into the circulation of blood: http://www.bbc.co.uk/history/historic_figures/harvey_william.shtml