Mechanical Transients and the Origin of Muscular Force

The invitation to eontril)ute to a symposium of this kind gives an opportunity for writing in a more discursive, and a more speculative, way than is accepted in papers for regular scientific journals. An invitation in 1955 to contribute to Progress in Biophysics gave one of us a similar opportunity (A. F. Huxley, 1957) to present some ideas on the (letails of the contraction mechanism that had arisen through thinking in terms of the sliding-filament heory. Our experimental work since then has consisted largely in following up some of the consequences of those ideas, and it is therefore appropriate to combine a discussion of otu present ideas on the origin of force in a contracting muscle fiber with a review of the scheme put forward in