123 



141. MUSCLES, MUSCULI, 



form the soft fibrous organs, the substance of which is known by 

 the name of flesh, and which, by the capacity they enjoy of con- 

 tracting, produce, in an especial manner, the movement which is 

 permitted by the articular connection of the bones and the mo- 

 bility of the soft parts. They consist, independently of fibro- 

 cellular tissue, vessels and nerves which enter into their formation, 

 of a peculiar tissue which is closely related to that of the con- 

 tractile coat of vessels. 



142. a. Tissue of muscles. 



Every muscle is composed of a number of bundles of fibres, each of which 

 again consists of filaments which are even once more divisible ; so that we 

 may distinguish primary, secondary, and tertiary divisions. All are united 

 together by a general fibrous envelope, perimysium, as well as each being sur- 

 rounded by its own particular investment, which connects it with the sheath. 

 The tertiary bundles are three-sided, prismatic, about 2 /// broad, and consist of 

 the flat secondary divisions, lying longitudinally to one another, J to #" broad, 

 which on their side are formed of the red or pale, flat, fine primary divisions, 

 0-005'" in diameter. 



In the primary bundles we observe under the microscope many, 10 to 500, 

 longitudinal striae, which also display many delicate filaments, fibrillae, primi- 

 tive filaments, lying parallel to one another, appearing of a yellowish red, and 

 perforated by transverse striae, or even only little points, whereby an angular, 

 articulated appearance is produced. Whether a canal exists in the axis of 

 the primary bundle, filled with a gelatinous substance, as in the Embryo, ac- 

 cording to Valentin, is still doubtful. The longitudinal striae, even the primi- 

 tive filaments also, and transverse striae, are not found in all muscles. 



Hence we distinguish, transversely striped, striated [compound] (varicose, 

 articulated), and unstriped [simple] organic muscular fibres. 



1. To the striated belong all the so-called animal, or muscles of voluntary 

 movement, and of the heart. 



2. To the unstriped all the so-called organic, or muscles of involuntary 

 movement, with exception of the heart. 



143. b. Characteristics of muscular tissue. 



1. Chemical. It is little changed by water and spirits of wine; very easily 

 decomposes, and at last breaks up by means of Gastric juice into globules, but 

 yields on boiling only very little gelatin (from the sheaths). Primitive fibres 

 and sheaths are soluble in concentrated, are rendered transparent and soft by 

 dilute acetic acid ; by Potass, carb. firm, in consequence of which the wave- 

 like and cylindrical form of the fibres shows very distinctly. 



Chemical constituents: much water (0-77), Albumen, and Hsematin, Al- 

 coholic and watery extract, with some phosphorus, soda, and lime, and lactic 

 acid; lastly, fibrin, fat, and gelatin. 



2. Physical Characters. The red colour of the muscles is not dependent 



