As the Study of Physick has differ'd in every Age, ac-cording to the prevailing Opinions and Ambiguous De-terminations of Philosophers, so the Practice of Midwifery has also varied, according to the Judicious Experiments and successful Operations of Professors; until of late Years, by the many happy Discoveries and strict Inquiries made into the Secrets of Nature, and Natural Causes, these Healing and obstetricious Arts are so much improv'd and advanc'd,...