LESSON 69.] MUSCULAR FIBRE. 231 



parity of size in that figure and this, there can be no doubt that the 

 structure is the same. 



1025. It is by no means the least remarkable fact that a tissue 

 purely animal, as is the muscular fibre of animal life, should exhibit 

 in its elements the true characteristics of a vegetable origin, and, still 

 more, of a lowly vegetable, such as an alga, but here we may trace 

 a distinct connection between the lowest plants and even the highest 

 animals. 



1026. The ultimate element of a muscle, therefore, is a single 

 nucleated cell, such as forms the sole element of thousands of plants. 



1027. Neither does the analogy end here, for it is well known 

 that in muscular fibre the cells are firstly formed, and the nucleus 

 (sarcous element) subsequently placed therein. 



1028. It is highly probable that the sarcous elements of muscle 

 possess the same generative power as the nuclei of plants, and that 

 the tissue is extended by the subdivision of the sarcous element, and 

 the cell containing it. 



1029. Very thin transverse sections of muscle show merely a 

 series of minute round dots the sarcous elements each one being 

 surrounded by a small circular white ring, de- Fl(J 



noting the position of the rectangular body 

 within the tube (Fig. 359). 



1030. The muscles of organic life, or vol- 

 untary muscles, as they are called, differ in 



structure from the preceding. Transverse Action of 



1031. They form a closer and more com- muscle> 



pact tissue, and are far more difficult to manipulate with than the 

 muscles of animal life. 



1032. It sometimes happens that their size is less than the fibres of 

 the striped muscle, although in some animals the contrary is the fact. 



1033. These plain, non-striated fibres, are arranged like the 

 fibres of the other muscles, in a parallel manner, into bands, or 

 fasciculi ; but the fasciculi are usually woven into a network not 

 having any fixed points of attachment. 



This is the nature of the muscular coat of the ossophagus, sto- 

 mach, intestinal canal, &c. ; it also occurs in most of the large gland 

 ducts, and in the iris (curtain of the eye). 



1034. The Heart is composed of various forms of muscular fibre ; 

 some being distinctly striated, others quite plain, and others of in- 

 termediate character. 



1035. The chief characteristic form of the non-striped muscular 



