Rothschild M A, Schmidt V, Schneider V
Institute of Forensic Medicine, Freie Universität Berlin, Germany.
Med Law. 1996;15(2):329-35.
Establishing the length of time since death is particularly difficult in corpses showing advanced autolysis. One sign of advanced decay is the formation of adipocere. In this state bodies show evidence of a partly wax-like and partly pasty condition. Continued storage ultimately results, among other things, in further decomposition due to the action of micro-organisms from the surrounding area-even if this is chronologically delayed. An exception is provided by the formation of adipocere under air-tight conditions. Initially, autolysis and heterolysis also occur, involving the release of fatty acids. As a result of the subsequent hydrogenation of the fats under the influence of bacterial enzymes, the unsaturated fatty acids are partially converted into saturated fatty acids. As the fatty acids clearly have a bactericidal effect, further bacterial decomposition is stopped at this early adipocere stage. Additional micro-organisms from outside can no longer penetrate when this hermetic seal is in place. In addition, the lack of calcium (e.g. from water or moist earth) can be a reason for the fact that further adipocere development, leading to wax-like hardening of the fat, is arrested. Thus the condition of the body can remain constantly preserved over many years and it no longer allows a reliable estimate to be made of the period of time since death.
对于呈现高度自溶现象的尸体而言,确定死亡时间尤为困难。尸体高度腐败的一个迹象是尸蜡的形成。处于这种状态的尸体呈现出部分似蜡状且部分似糊状的特征。持续存放最终会导致诸多后果,其中包括由于周围环境中微生物的作用而进一步分解,即便这种分解在时间上会有所延迟。在密封条件下形成尸蜡则是一个例外情况。起初,自溶和异溶过程也会发生,这涉及脂肪酸的释放。在细菌酶的作用下,随后脂肪发生氢化反应,不饱和脂肪酸部分转化为饱和脂肪酸。由于脂肪酸显然具有杀菌作用,在早期尸蜡阶段,进一步的细菌分解就会停止。当这种密封状态存在时,外部的其他微生物便无法再侵入。此外,缺乏钙(如来自水或潮湿土壤)可能是导致尸蜡进一步发展(致使脂肪呈蜡样硬化)受阻的一个原因。因此,尸体状况能够多年保持不变,这使得人们无法再可靠地估计死亡后的时间。