Memoirs: Engelmann on Contractility and Double Refraction

Abstract

ABSTRACT After referring to Boeck’s original discovery of the phenomenon of double refraction in muscles, and to Brücke’s classical memoir, Engelmann states that in spite of proofs being brought forward of the association of other forms of contractile phenomena with the presence of double refraction, e. g. in the muscles of certain infusoria, the results were almost all negative. In consequence, the opinion prevailed that the presence of anisotropous elements in muscle was a curious rather than an important phenomenon. This point of view was modified when it was shown by Engelmann himself (Pflüger’s ‘Archiv,’ Bd. 7) that contraction is exclusively connected with the double-refracting layers in striped muscle. The supposition then arose that, as a general law, contraction might be dependent on the presence of double-refracting particles, especially as the boundaries between different forms of movement in protoplasm and in muscle formerly assumed to be so sharply defined had broken down.