74 TRANSVERSELY STRIPED MUSCULAR FIBRES. 



perfectly adapted for the determination of the sulphur and for the 

 elementary analysis generally, after it has been extracted with 

 alcohol and ether. The substance composing the nuclei of the 

 fibre-cells cannot be obtained in an equally pure state, since its 

 best solvent is a dilute solution of soda, which always dissolves 

 some of the connective tissue, or, at all events, occasions the 

 gelatinous parts to pass through the filter. 



We abstain from making any remarks on the method of 

 examining the parenchymatous fluid, partly because we have 

 already frequently spoken of the mode of determining the indi- 

 vidual constituents of the animal fluids, and partly because we 

 shall have occasion to revert to this subject under the head of 

 the Striped Fibres. 



TRANSVERSELY STRJPED MUSCULAR FIBRES. 



THESE textural elements, which have also been termed animal 

 (Breschet), or articulated (Treviranus) muscular fibres, or bundles 

 of contractile fibrils (Kolliker), are peculiar to those organs of 

 motion which, at least to a certain extent, are subject to the will. 



If we examine any muscle (as, for instance, one of the 

 abdominal muscles) in both longitudinal and transverse sections, 

 we perceive, even with the naked eye, that it consists of a more or 

 less considerable number of parallel, longitudinally striped bundles 

 (the secondary muscular bundles), which are surrounded by con- 

 nective tissue (perimysium internum), serving to unite them together. 

 In this connective tissue we may trace, on a careful examination, 

 a few blood-vessels and nerves ; but when we examine these 

 striped bundles under the microscope, we perceive that the longi- 

 tudinal stripes are dependent on yet finer bundles, which may be 

 recognised under higher magnifying powers as roundish, irregu- 

 larly flattened cylinders or strings, whose transverse section occa- 

 sionally appears hexagonal, and which exhibit distinct transverse 

 striation. A more careful examination of these very fine, trans- 

 versely striped bundles (primitive muscular bundles) shows that 

 they consist of closely approximating, necklace-like filaments, 

 which are closely surrounded by a homogeneous smooth investment 

 (sarcolemma). This investing membrane of the different primi- 

 tive bundles is held together by filaments of connective tissue ; 



