JUN I 6 1891 



On the structure of cross-striated muscle 



by 

 E. A. Schäfer, F. R. S. 



Professor in University College, London. 



(With pi. XV— XVII.) 



page 



Contents. 



The present position of the question. Consensus of opinion as to structural 

 appearances. Sarcoplasm theory of Rollett. Reticulum -enchylema 

 theory of Carnoy. Essential identity of leg- and wing-muscles of insects. 

 Is the reticulum or sarcoplasm contractile or not? Consideration of 

 the reticulum - theory of protoplasm. Structure of the protoplasm of 

 the white corpuscle 178 



Appearances of the ordinary muscles (leg -muscles of insects). Effect of 

 focussing upon these appearances. Reasons for regarding the deep 

 focal appearances as illusory 185 



Definition of terms: general results arrived at 190 



Evidences of pre-existence of longitudinal elements. The question of fibril- 

 lation considered. The longitudinal lines of the reticulum of „acid" 

 and „gold" muscular fibres are the optical expression of planes of 

 separation between muscle-columns or sarcostyles. The presence and 

 nature of the sarcoplasm. Special characters of the „transverse net- 

 works" of Retzius 192 



The structure of the wing -muscles of bisects. Their appearances in the 

 fresh condition and after the action of reagents. Sarcous elements. 

 Their tubular composition. Differences exhibited by the wing-muscles 

 in the extended and contracted states. Reasons for regarding the iso- 

 lated elements of the wing-muscles as equivalent to the sarcostyles or 

 muscle-columns of the leg-muscles. Are the latter fibrillated? . . . 202 



Production of the cross-striae and their relation to the structure of muscle. 

 Striae of the wing-muscles. Their changes with extension and in con- 

 traction. Probable identity between contraction and retraction. Striae 

 of the ordinary muscles. Influence of the sarcoplasmic enlargements 

 on their striation. Changes in extension and contraction. Apparent 

 reversal of striae in contracted fibre. The accessory disks .... 219 



Conclusions 233 



Description of figures 236 



Internationale Monatsschrift für Anat. xh Phys. VIII. \0 



