OBSERVATIONS ON THE STRUCTURE AND DISTRIBU- 

 TION OF STRIPED AND UNSTRIPED MUSCLE IN 

 THE ANIMAL KINGDOM, AND A THEORY OF 

 MUSCULAR CONTRACTION. 



By C. F. Marshall, M.Sc, Piatt Physiological Scholar in 

 the Owens College, Manchester, 



[With Plate VI.] 



Striped muscle has long been known to occur widely distributed 

 in the animal kingdom, but the details of the structure of the 

 striped muscle-cell have been the subject of much controversy. 

 Various descriptions have been given, widely differing from one 

 another, and none of them affording a satisfactory basis of com- 

 parison with other cells. The demonstration of an intracellular net- 

 work in the muscle-fibre by several recent observers appears to 

 afford the most rational clue to its structure, for it not only explains 

 all the appearances seen in the muscle-fibre, including those seen 

 with polarised light in the living fibre by Briicke, but it also renders 

 possible a comparison with other cells, and shows that a muscle-fibre 

 is to be regarded as of essentially the same structure as an ordinary 

 cell, and must not be considered as an enigmatical structure, the 

 details of which do not correspond to those of any other cell in the 

 animal economy. 



It is necessary first to examine the descriptions of the several 

 observers who have described a network in the striped muscle-fibre, 

 and to consider the interpretation that they have put upon it. In 

 the following account I have only referred to those observers who 

 have described some form of network in the muscle-fibre, 



