Since the discovery of endotoxin a hundred years, people have always believed that endotoxin, as a structural component of the bacterial cell walls, can only be released when the cell is dead or artificially lysed. However, in recent years, it has been found that gram-negative bacteria also release endotoxins during the logarithmic growth phase of bacteria or when the bacteria are deficient in nutrition.

The electron microscope technology found that during the logarithmic growth period of bacteria, the outer membrane of gram-negative bacteria was over-synthesized, and the excess outer membrane formed many "structure afblebs" on the surface of the cell, and the endotoxin was released into the surrounding media in the form of "herpetic". There were two types of "herpetic" on the outer membrane of the cell, and the "large herpetic" formed in the process of cell division and septum generation, Die as the cell divides into two bacteria; "Small blisters" exist on the outer surface of the bacterial body, which is constantly produced during the bacterial growth process and released into the external environment at any time. Although the free endotoxin only accounts for a part of the total bacterial endotoxin, it is worth noting that the continuously released endotoxin may play an important role in its response to the host.