[Effect of muscle storage and stimulation on the intensity of Z-reflection of its equatorial x-ray pattern]

The maintenance of frog sartorius muscle in Ringer solution over a long period of time (24 h or more) increases Z-reflection intensity of equatorial X-ray pattern relative to that from fresh (1-2 h) dissecting muscle at sarcomere length more than 2.3 m. Long stimulation deteriorates the equatorial X-ray pattern from muscle. Then with the course of time Z-reflection intensity increases several times, Z and reflections merge, and rigor equatorial X-ray pattern is registered.