RESUMEN
The present study was carried out on 18 cats classified into 2 groups according to the mode of death. The 1st group was submitted to asphyxial death, while the 2nd group was submitted to cut throat [the target was the neck vessels to cause fatal hemorrhage]. In both groups, the effect of the cause of death on estimation of early P. M. interval was measured from the response of skeletal muscle to electric simulation and the changes of ATPase enzyme in the tested muscle. From the obtained results, it was found that in asphyxia death, the mean total time of early P. M. interval was 34.7 minutes; while in cut throat, it was 117.1 minutes. In both methods, there was significant gradual decrease in the amplitude of contraction accompanied with gradual decrease in the activity of ATPase enzyme. Thus, it could be concluded that the mentioned causes of death affect the measurement of early P. M. interval. Also, there is arelationship between the amplitude of muscle contraction and the activity ofATPasa enzyme of the tested muscle