236 THE MUSCLES. 



into gelatine by boiling in water ; but its largest portion is a nitrogenous sub- 

 stance, soluble in dilute hydrochloric acid, called myosine, or muscular fibrine ; it 

 differs but little from the fibrine of the blood. 



Physiological Properties of the Striped Muscles. 



In this paragraph will be discussed the development of the muscles, muscular 

 contractility, and the part the muscles play in locomotion, 



A. Development of the Muscles. — A muscle is derived from a mass of 



Fig. 152. 



T' 



ARRANGEMENT OF THE FIBRES OF A MUSCLE. 



153- 



M, Body of a muscle. T, t', Tendon, a, b, Length of the body of the muscle. A, B, C, D, Various 

 modes of arrangement of the muscular fibres. (From Beaunis and Bouchard's Anatomiff 

 descriptive.) 



embryonic cells. Each cell becomes considerably elongated, and its nucleus 

 multiplies, the nuclei extending along the course of the fibre. The cellular mem- 

 brane, enormously developed, forms the sarcolemma ; while the contents of the cell, 

 becoming more dense, divide longitudinally, and give 

 rise to the sarcous elements. When the muscles are 

 formed, they grow by the augmentation in length 

 and thickness of their primitive fibres. 



B. Muscular Contractility. — Muscles pos- 

 sess the property of contracting under the influence 

 of a natural or artificial stimulus. Muscular con- 

 traction is the phenomenon resulting from the opera- 

 tion of this property. Muscles in a state of contrac- 

 tion are the seat of physical and chemical phenomena ; 

 they change their form and consistence, and produce 

 a relatively abundant quantity of carbonic acid, 

 creatinine, and inosinic acid. During contraction, it has been remarked that the 

 muscular fibres contract by increasing in volume, like an india-rubber tube left to 



distribution of CAPILLARIES 

 IN MUSCLE. 



