J 868.] On the intimate Structure of Muscular Fibre. 73 



of homogeneous tissue. I believe therefore that a voluntary muscle 

 consists of a matrix of fibrous tissue the interstices of which are filled 

 up with contractile fibres such as I have just described, the largo? 

 vessels and nerves ramifying in the fibrous matrix, but giving off 

 numerous branches which spread themselves over the case of homo- 

 geneous tissue which encloses each individual contracting fibre, so that 

 the capillaries and ultimate branches of the nerves are brought into 

 immediate contact with the contractile tissue. 



II this be the solution of the vexed question as to the minute anatomy 

 of muscle, it certainly appears like many other things to be remarkably 

 simple, when once we understand them, and to be another instance of 

 the wonderful adaptation of means to an end, which is displayed in every 

 part of the body. Evidently bands of simply elastic tissue could not per- 

 form the functions required of a muscle, the increase in breadth of the 

 muscles of a limb in contracting would, under these circumstances, 

 exercise an injurious amount of pressure on the nerves and vessels of 

 surrounding parts, and as the elastic bands became elongated, spaces 

 would necessarily be left between them, which had previously been occu- 

 pied by the bulk of the contracting muscle. All such anomalies are 

 obviated by the beautiful arrangement I have now demonstrated, for in 

 contraction the longitudinal bands must shorten on themselves drawing 

 the transverse bands into close approximation, and these at the same 

 time uncoil, each fibre therefore would increase in breadth exactly to 

 the same amount which it lost in length. That such is the case with 

 regard to the muscles of a limb as a whole, has been proved by repeated 

 measurements. Mr. Bowman remarks « a muscle in the act of contract- 

 ing becomes shorter and thicker, the changes being accurately 

 proportioned to one another, the whole organ neither gaining nor 

 losing in bulk." But the means by which these changes are effected 

 have never been explained satisfactorily before, so far as I am aware. 

 One can hardly be certain as to the active part taken by the transverse 

 bands during muscular contraction. It is evident as the longitudi- 

 nal bands are attached to fixed points at either extremity, that the 

 tension or relaxation of the transverse bands would be sufficient of 

 themselves by acting on the longitudinal bands to cause contraction 

 or relaxation of the muscle ; and I am disposed to favour this idea, 

 because we can thus easily conceive the means by which the remarkably 



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