The blood cells of the horseshoe crab are primitive and have no division of labor, but this simple primitive cell has magical functions. When bacteria and viruses come into contact with the horseshoe crab's blood, the amebocytes in the horseshoe crab's blood will release a coagulation protein that causes the blood to quickly coagulate and prevent bacteria from multiplying. Like a barrier, it can effectively prevent other bacteria from invading.

In addition, the blood of horseshoe crabs also contains a substance called "limulus amebocyte lysate" (LAL), which can be used To develop reagents for testing vaccines and drugs for bacterial contamination. At the same time, this substance can also be used to detect toxin contamination in the pharmaceutical and food industries, and can quickly and accurately detect whether the internal tissues of the human body are caused by bacterial infection.