Putrefaction Research

Putrefaction research is the study of decaying matter upon an organism's death. Although this area of inquiry extends to both the plant and animal worlds, the latter is the focus of this entry. When an animal dies, including human beings, there is a series of stages in which the body breaks down, or decomposes, into simpler states of matter. Within 5 minutes of death, the human body begins to decompose and will continue to do so in stages until it is reduced to mere skeletonized bone. This initial stage of decomposition can take anywhere from a few days to years, depending upon where and how the corpse is preserved and under what environmental conditions, as both factors greatly influence the rate of decay. The first stage of animal decomposition, called autolysis, or self-digestion, begins nearly immediately following the lack of oxygen in [Page 830]the body. Without sufficient oxygen, cells are unable to excrete and process carbon dioxide, which results in an elevated pH level in the blood. This, in turn, poisons the body's cells and causes them to rupture, releasing cellular nutrients. Autolysis, which is an internal process whereby the body's chemicals control tissue decomposition, eventually affects every cell, typically within a few days after death has occurred. As more and more tissue and organs break down, the body begins to become fluid-like and is marked by blisters and skin slippage.

Cellular breakage continues until no oxygen remains in the body, signaling the beginning of putrefaction, a process during which microorganisms, including bacteria, fungi, and protozoa, break down the remaining soft tissues. These microorganisms ensure that the body's tissues become volatile organic compounds (VOCs), which are gases (e.g., hydrogen sulfate, carbon dioxide, methane, and ammonia) and liquids that physically alter the corpse. These VOCs attract a plethora of insects, most notably Sarcophagidae (flesh flies) and Calliphoridae (blow flies) in the early stage of decomposition, which then lay eggs on the body and feed off of the flesh.

During the putrefaction process, the body undergoes physical changes. Blood begins to pool after death and hemoglobin is broken down into sulfa hemoglobin, resulting in the corpse's now greenish hue (liver mortis). This hemolyzation process, aided by bacteria, also results in the formation of red marks along the body's veins. In time, the red markings will then turn a shade of green, a process in putrefaction called marbleization. As microorganisms continue to decompose tissues, more gases are released from the cells, especially those in the abdomen and face, and the body becomes visibly bloated and marked by a strong odor. The stomach and intestines become so laden with gases that their contents eventually submit to the pressure and are expelled from the anus. There is an increase in insect activity as compared to during the autolysis stage, although it is characteristically the same Calliphoridae family of insects. It is especially common in warm environments for the body to undergo saponification, the development of a pale yellow waxy or slick substance, called adipocere formation, when the body's fat deposits turn into soap due to elevated pH levels caused by bacterial activity.

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