In view of the high content of fluorine in the water in Guangdong pro-vince,we detected the serum fluorine level in rabbits died of drowning andcompared with that obtained from rabbits immersed in water after deathfrom hanging.The fluorine content in water is about 15 folds higher than normal whilein control cases the serum fluorine values are slightly lower than normal.The fluorine content in human serum is similar with that of rabbits.Itsuggests that detection of serum fluorine content might be a valuable methodfor the diagnosis of drowning in those areas where there are high waterfluorine content.

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.