PART II. 



CHAPTER X. 



MUSCULAR FIBRE. 



BY THOMAS DWIGHT, M.D., 



Instructor in Topographical Anatomy and in Histology at Harvard University. 



THE physiological attribute of muscular tissue is contrac- 

 tility. This may or may not be under the control of the will. 

 The structure of voluntary muscular fibre is very different from 

 that of the involuntary. 



This distinction, however, is not absolute. The muscular 

 fibre of the heart presents a structure intermediate between the 

 two typical forms. Striped fibres are found in some places, as, 

 for instance, in the upper part of the oesophagus, over which 

 most people have little or no control. There is also an un- 

 doubted difference in the manner of contraction among volun- 

 tary muscles. Whether this is associated with a difference of 

 structure is an interesting but very uncertain question that 

 will be alluded to later. 



INVOLUNTARY MUSCULAR FIBRE. 



Unstriped muscular fibre is shown with great advantage in 

 the bladder of the frog. It should be stained with gold chlo- 

 ride, logwood, or carmine. 1 After the specimen has lain two 



1 If one's object is to study the muscular tissue only, gold has no advantages over 

 the other agents, and should not be used, because it is less certain. The writer has 

 obtained remarkably beautiful stainings of the bladder by using carmine, following 

 Beale'o method. 



