Thanatochemistry

Thanatochemistry (from the Greek θάνατοζ, Thanatos, the personification of death in Greek mythology) is broadly defined as the chemistry and chemical aspects of those sciences related to mortuary practice. In particular, modern thanatochemistry encompasses embalming, the temporary preservation of human remains that enables them to be presented intact at a funeral ceremony. Thus, the objective is to overcome the effects of decay, a natural consequence of time.

One of the earliest manifestations of embalming was mummification, developed by the ancient Egyptians several thousand years before the common era. The Egyptians were motivated by spiritual or superstitious notions that after death, preservation empowered the soul of the deceased, which would then return to the corpse. The abdomen was opened and all the organs removed. The emptied body was then coated in natron (hydrated sodium carbonate), which facilitated drying. When in contact with moisture, it gives alkaline solutions, which provide a hostile environment to putrefying bacteria. The treated corpse was then wrapped in linen and canvas, and put to rest inside a tomb.

Mummification of a corpse need not necessarily involve any deliberate intervention. Naturally occurring, albeit extreme, environmental conditions have resulted in similar preservation, as evidenced by recent discoveries of naturally mummified remains; for example, the colloquially named Otzi the Iceman, discovered in a glacier of the Otztal Alps, 1991, and the Tollund man found buried in a peat bog on the Jutland Peninsula in Denmark in 1950 were both found in remarkable sates of preservation due to anaerobic and very cold and acidic conditions, respectively.

Shortly after the conclusive identification of the chemical formaldehyde by German chemist August Wilhelm von Hof mann in 1867, its preserving properties were discovered, and it is now the basis of contemporary methods of embalming. Aqueous solutions of formaldehyde (with trade names such as Formalin or Formol) kill living cells, both tissue and bacterial, by dehydration of cytoplasmic fluids and coagulation of the constituent proteins by their reaction with the primary amine groups of [Page 1246]peptides in the formaldehyde. Aesthetically, color changes produced during this reaction can give the appearance of blood flowing under the skin. The moisture within the cell is replaced with a rigid gellike material, which allows the embalmed tissue to retain its structural integrity. Moreover, the tissue can resist any subsequent bacterial attack.

Embalming fluids are injected directly into the arteries of the deceased. A concentrate of arterial chemical (based on a mixture of formaldehyde, glutaraldehyde, or in some cases phenol) is diluted and mixed with nonpreservative ingredients to give a case-dependent solution of embalming/arterial fluid, which is administered. The proportion of arterial chemical is dependent on the required longevity of preservation. Some additional coin-jectants include water modifiers to maintain optimum alkalinity of the solution; dyes; humectants, which give dead tissue a hydrated and natural appearance; and cell conditioners to prepare for fluid absorption and to remove blood clots.

Despite its success as a preservative, formaldehyde has been shown to be a potent carcinogen. with many other ingredients of embalming fluids also known to be toxic, the search for safer arterial chemicals is ongoing.

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