284 STRUCTURE OF MUSCULAR FIBRES. 



Bowman and Wilson each ultimate fibril of animal life is com- 

 posed of a succession of cells, united by their flat surfaces, each 

 cell filled with a transparent substance, the essential element of 

 the muscle, termed by Mr. Wilson myoline. The development 

 of muscular fibre is supposed to take place by the intuitive 

 formation of cell germs, out of an original plastic deposit, a sort 

 of soil for the germs or cytoblasts, called the blastema. 

 — The primitive fasciculus, or muscular fibre of organic life, 

 which is solely under the influence of the ganglionic nervous 

 system, is paler and softer than those of animal life ; is not so 

 regularly arranged in a longitudinal and parallel direction ; 

 and is less easily divided into Its primitive filaments. Though 

 each fibre is round if singly examined, the bundles which they 

 form are flattened, composing muscular membranes, often two 

 or three layers deep, the bundles crossing each other at differ- 

 ent angles, and forming networks and gratings. The most 

 remarkable character of the organic muscular fibre, is the 

 existence in it here and there of swellings somewhat larger 

 than the diameter of the fibre, and produced by the nuclei of 

 the original nucleated cells from which the fibre was devel- 

 oped.* — 



These fibrillag have been represented as simple hollow tubes, 

 as a series of globular vesicles, as continuations of arteries, as 

 termination of nerves, as structures of rhomboidal bodies, and 

 finally, as cellular.f 



It is supposed by one of the latest observers, who appears to 

 be entitled to great attention,! that the muscular fibres are not 

 thus minutely divided : that a single fibre, when separated from 



* For a more full and interesting account of these microscopical investiga- 

 tions, see Human Physiology, fourth edition, by R. Dunglison, M. D., Professor 

 of the Institutes of Medicine and Medical Jurisprudence in Jefferson Medical 

 College, &c. &c. Phila., 1S45.— p. 



f A statement of these descriptions, with reference to the publications in 

 which they are contained, may be seen in the Elementa Physiologiae of Haller, 

 vol. iv. 



:j: Carlysle, in the Croonian Lecture, London Phylosophical Transactions, 

 1805, Part L 



