Aggregation of isolated myofibrils stimulated by their contraction. I. Origin of the second phase of optical changes during myofibril contraction

Aggregation of contracted myofibrils was shown to be responsible for spontaneous: slow reduction of optical density of myofibril suspension on the final stage of their contraction. This effect faded with an increase in light wavelength, with increased angle of view of the photocell and diminished sizes of myofibrils.