RESUMEN
For the purpose of timing of wounds,the measurement of K~+/Na~+ ratio of 36specimens of wister rat's muscles taken from the local burn area by the atomicabsorption spcetrophometry was carried out.The results showed that K~+/Na~+ ratio in specimens of burn formed 15,30,60minutes before death and 20 minutes after death reduced 47～82%(mean 71%),56～89%(mean 77%),69～94%(mean 86%)and 4～38%(mean 27%)respectively ascompared with the control muscles.Reduction rate of K~+/Na~+ ratio in ante-mortem group was more obvious than the postmortem ones.With the prolongationof the antemortem interval,the reduction of K~+/Na~+ ratio becomes more marked.We believe that this method is a simple and reliable method in timing woundsand it is valuable in forensic medicine practice.