80 • Arthur C. Aufderheide and Mary L. Aufderheide 



sacrificial victim entombed above the frost Hne on an Andean 

 mountain at an ahitude of 5400 m (Mostny 1957; Schobinger 

 1966), Scythian tribal chiefs (Artamonov 1965) and Arctic 

 expedition members (Beattie 1983; Paddock etal. 1970) bur- 

 ied in tombs dug into permafrost areas. Although most of 

 these were probably continuously frozen, cooling near but 

 not necessarily below the freezing point (as in Arctic summer 

 thaw periods) may inhibit enzyme action at least to the point 

 of profound retardation, as it did in several 650-year-old Inuit 

 bodies from Alaska (Zimmerman and Aufderheide 1984). Of 

 interest here are Micozzi's experimental taphonomy studies 

 demonstrating delayed soft tissue putrefaction at summer 

 outdoor temperatures following a brief period of body freez- 

 ing immediately after death (although the mechanical effects 

 of freezing actually hastened disarticulation). Micozzi 

 ( 1 986) felt this was the result of substantial intestinal bacteri- 

 al mortality during the period of freezing. 



Warming the body may also retard putrefactive chemical 

 reactions. Since intestinal bacterial growth in vitro fre- 

 quently ceases at incubation temperatures only a few degrees 

 above body temperature, the delaying effect of wanning may 

 be operative both at the bacterial level as well as creating an 

 environmental temperature substantially deviant from the 

 optimum for some enzymes. Heat generated by intestinal 

 bacterial activity in a living individual is normally di.ssipated 

 by intestinal wall blood flow. When this cooling flow of 

 blood ceases after death, intra-abdominal temperatures have 

 been shown to rise. Native Aleuts exploited this preserving 

 effect by first heating their deceased tribal leaders' corpses 

 over a fire and then placing them in a cave continuously 

 warmed by a natural volcanic heat source (Alexander 1949; 

 Zimmerman et al. 1981:640) In the southwestern United 

 States, bodies of pre-Columbian North American natives 

 were sometimes buried in stone-lined cists exposed to the hot 

 summer sun. Conceivably, elevated ambient temperature 

 may have been the principal factor in delaying putrefactive 

 enzyme activity until the corpse became very dry (El-Najjar 

 et al. 1985). Such effects probably require substantial tem- 

 perature elevations since only mild rises, although perhaps 

 inhibiting bacterial growth, may accelerate the proteolytic 

 activity of certain enzymes. 



CHEMICAL ACTION 



There are few well-documented instances of spontaneous 

 mummification largely due to an environmental al i eration 

 OF pH, although this possibility is seldom pursued vigorously 

 by investigators. The well-known tissue-preserving effect of 

 encasing a corpse in highly alkaline, powdered lime testifies 

 to its potential effectiveness. It is conceivable that water 

 percolating through a limestone soil may become sufficiently 

 basic to paralyze enzymatic activity when it saturates a body 

 buried therein. 



Heavy metals are powerful enzyme poisons. This is, for 

 example, the principal mechanism of lead toxicity in living 



individuals. Arsenic is so effective that it was used com- 

 monly as an intra-arterial injection method of embalming by 

 American morticians until the early part of this century 

 (Snow and Reyman 1977). Arsenic was accumulated during 

 life in the bodies of pre-Columbian natives of northern 

 Chile's Camarones Valley as a result of drinking water from 

 the valley's arsenic-contaminated river. This may have con- 

 tributed to the excellent state of preservation present in these 

 bodies (M.J. Allison, pers. comm.). 



The ABSENCE OF OXYGEN is commonly invoked as an ex- 

 planation for postmortem soft tissue preservation, though it 

 is difficult to identify a well-controlled, laboratory study 

 establishing this conviction. The astonishing quality of soft 

 tissue preservation in the body of a Chinese noblewoman 

 from 100 B.C. has been attributed to the assumed anoxic tomb 

 environment, though the assignment of oxygen absence as 

 the principal factor in that case was done by exclusion of 

 other apparent possibilities (Wu et al. 1980). 



In addition to the action of heavy metals and the chemical 

 methods listed below, occasionally specific antimicrobial 

 SUBSTANCES may be present which delay degenerative pro- 

 cesses by inhibiting bacterial proliferation. Probably the best 

 known of these is the production of tetracycline by the mold- 

 like bacteria Streptomyces. Ingestion of this antibiotic by a 

 living individual for infection control has been found to cause 

 a specific, fluorescent staining of bone collagen. Detec- 

 tion of a similar staining pattern in archeological (Nubian) 

 bones (believed to be the result of eating Streptomyces- 

 contaminated grain) demonstrated that accidental antibiotic 

 ingestion occurred during antiquity (Bassett et al. 1980). 

 Aspergillus fla\ us. which flourishes in grain, also produces a 

 chemical with antibacterial action: aflatoxin. Theoretically 

 such a mechanism might contribute to soft tissue preserva- 

 tion after death. 



One reason living cells survive the frequently complex 

 chemical milieu commonly present within intracellular en- 

 vironments of living biological systems is that most enzymes 

 are designed to respond to only a very narrow range of mo- 

 lecular structures. This high degree of specificity for en- 

 zymes' intended substrates makes possible the success of 

 tissue preservation by the use of "fixing" substances like 

 formaldehyde or certain alcohols which so radically re- 

 arrange proteins' molecular contour that proteases which are 

 commonly present post mortem no longer react with them. 

 Tannic acid is a fixing agent commonly employed today by 

 taxidermists to preserve animal skins. The presence of tannic 

 acid in many northern European swamps is believed to be 

 responsible for the frequently excellent preservation of the 

 "bog people" mummies found within them (Glob 1965:1- 

 45). 



Adipocere formation is initiated in the form of neutral 

 fat hydrolysis by endogenous lipases subsequently modified 

 by bacterial enzymes (usually of clostridial origin) resulting 

 in the formation of a different group of fatty acids which are 

 relatively insoluble and chemically poorly reactive. These 



Zagreb Paleopathology Symp. 1988 



