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On the Eclations of the isotropous to the anisotropous 

 Layers in striped Muscles. 



By 



Henry M. Bernard, M. A., Cantab. 



(From the Huxley research laboratory, South Kensington.) 



With Plate 29. 



In complete sections of small Crustaceans, specially fixed and 

 prepared for histological purposes, muscles are found in every stage 

 of contraction, many with the wave of contraction fixed in its course 

 (fig. 1 and 2). With a large selection of such slides at my disposal, 

 I have carried out a long series of measurements and comparisons 

 with the help of a Zeiss apochromatic homogeneous immersion lens 

 (1,4 n. a. 2"»°'), my object being to see whether the phenomena of 

 muscle contraction throw any light on Verworn's recently published 

 theory of protoplasmic movements *). 



It was obvious from the outset that Verworn's theory might be 

 brought into harmony with Schäfer's ^) interesting observations as to 

 the fine structure of the anisotropous layers in the wing muscles 

 of Flies. Indeed Schäfer, from the special study of these fibres by 

 means of photography, seems to arrive at almost the same conclusion 

 as Verworn from the study of the Protozoa, that muscle contraction 

 should be deduced from the simpler forms of protoplasmic movements, 

 i. e. from the extrusion and retraction of the pseudopodia of the Amoeba. 



Verworn, following Engelmann's dictum that the anisotro- 



1) Die Bewegung der lebendigen Substanz., Jena 1892. 



2) in: Proc. Roy. Soc. London, vol. 49, 1891, p. 280, and further 

 a summary in Q,uain's Anatomy, 10. ed. 



