LESSON 67.] MUSCULAR FIBRE. 



225 



that they give an idea of coarseness, and as such they have been de- 

 scribed; but a little careful examination of the subject will show 

 this opinion to be erroneous, for, on the contrary, the ultimate fibril- 

 lae in these animals are so remarkably delicate, that no amount of 

 magnifying power will succeed in showing a single transverse line 

 upon them, when examined singly in the mass they are seen. 



991. This is shown in Fig. 348, copied from a preparation of the 

 muscles of Blatta Americana, made to show the ultimate fibrillaj ; the 

 muscular fibres on either side (a, a) show deli- 

 cate transverse lines, but the fibrillse torn 



from, and still connecting them (6), do not 

 show the least indication of a transverse line, 

 still they are really there. 



992. So, too, 

 lulus (Fig. 349), 

 in which the lines 

 on the fibre are 

 very coarse, the 

 fibrillae liberated 

 at the end, are 

 singularly fine, 

 and display no 



transverse lines. Muscular fibre, B. Americana. Muscular fibre, itilus. 



993. If we examine a muscle of the higher animals by the naked 

 eye, it will be seen to consist of a bundle of fibres, running in the 

 direction of the long axis of the muscle, and connected by means of 

 areolar tissue. 



994. If a muscle be analyzed by dissection, it will be found to 

 consist of fasciculi, or bundles of fibres ; and if we succeed in ob- 

 taining an ultimate fibre, it will consist of a fasciculus or bundle of 

 ultimate fibrillce. 



995. An ultimate fibre exhibits, under the microscope, the longi- 

 tudinally arranged fasciculi of ultimate fibrillas, their number being 

 so great, however, that their precise structure cannot be determined 

 until separated. 



LESSON LXYII. 



MUSCULAE FIBEE, CONTINUED. 



996. In addition to the longitudinal lines, equi-distant trans- 

 verse lines, at right angles to the former, will also be seen, and the 



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