Final answer:
The embalming process uses the method of injecting arterial fluid while maintaining an open drain tube to displace blood and preserve the body.
Step-by-step explanation:
The drainage method you are referring to, which involves the injection of arterial fluid while maintaining an open drain tube, is commonly associated with the process of embalming within the field of mortuary science. In this method, arterial fluid is introduced into the body's arterial system, and as it circulates, blood is displaced and drains out of the body through a separate venous tube. It is crucial to balance the rate of arterial fluid injection with the drainage to maintain tissue preservation and prevent swelling or distortion.