MUSCLES. 365 



part of an inch in diameter ; whilst M. Easpail 1 considers, that the inti- 

 mate structure of the muscular tissue, when it is in its most simple state, 

 consists of a bundle of cylinders, intimately agglutinated together, and 

 disposed, in a very loose spiral form around the ideal axis of the group. 

 These tubes are filled with a substance not wholly miscible with water, 

 and may be regarded as elongated vesicles, united at each end to other 

 vesicles of a similar character. 



When a muscular fibre is seen through an ordinary microscope, it 

 appears to be composed of longitudinal filaments, each consisting of a 

 string of globules, about g^Wtn of an inch in diameter. "But with a 

 better instrument," says Mr. Mayo, 2 "such as that which Mr. Lister 

 possesses, the delusion vanishes, and the parallel lines, which traverse 

 the fibre, appear perfectly cle ( an and even. Mr. Lister politely gave 

 me an opportunity of examining this appearance, which was discovered 

 by himself and Dr. Hodgkin." 



Fig. 146. Fig. 147. 



Striated Muscular Fibres. 



Fig. 146. A. A small portion of muscle, natural size. B. The same magnified 5 diameters, of larger 

 and smaller fasciculi, seen in a transverse section. 



Fig. 147. A few muscular fibres, being part of a small fasciculus, highly magnified, showing the 

 transverse stria?, a. End view of b 6, fibres j c. A fibre split into its fibrillae. 



The researches of Mr. Bowman 3 and others are as follows. When 

 the smallest fibre, that can be seen by the naked eye, is examined by 

 the microscope, it is found to consist of a number of cylindrical fibres 

 lying parallel to each other, and closely bound together. These fibres 

 present striae one set of which is longitudinal, the other transverse. 

 When the fibres are separated from each other, and examined more 

 closely, they may be resolved into fibrillse, which, so far as at present 

 known, are the ultimate elements of muscular structure. They are 

 represented in Figure 153. The fibrillse are bound together by 



1 Chimie Organique, &c., p. 211, Paris, 1833. 



2 Outlines of Human Physiology, chap. iii. 3d edit., London, 1833. 



3 Philosophical Transactions for 1840; art. Muscle, Cyclop, of Anat. and Physiol., Part 

 xxiv., p. 507, July, 1842 ; and Todd and Bowman's Physiological Anatomy and Physiology 

 of Man, Part i., Lond., 1843. 



