Demonstration of ATPase activity in skeletal muscle fibers of the triceps muscle of arm in white rats during development

On the base of modified calcium and method from Zebe and Falk (1964) for demonstration of ATPase activity results at the long head of the triceps muscle of white rats aged 1, 3, 6 weeks and 3 month were shown. This method is proper to make visible alteration of the localisation of the reaction product during the postnatal development. Further investigations are necessary in order to correlate the steps of differentiation of muscle fibres with the strength of ATPase activity.