470 MOVEMENTS VOICE AND SPEECH. 



others, star-shaped. They possess one, and sometimes two or three clear, 

 ovoid nuclei, with distinct nucleoli. On the addition of acetic acid the cells 

 disappear but the nuclei are unaffected. It is impossible to give any accu- 

 rate measurements of the cells, on account of their great variations in size. 

 The appearance of the connective tissue, with a few cells and nuclei, is repre- 

 sented in Fig. 153. 



Between the muscles, and in the substance of the muscles, between the 

 bundles of fibres, there always exists a greater or less quantity of adipose 

 tissue in the meshes of the fibrous structure. 



Blood-vessels and Lymphatics. The muscles are abundantly supplied 

 with blood-vessels, generally by a number of small arteries with two satellite 

 veins. The capillary arrangement in this tissue is peculiar. From the small- 

 est arterioles, capillary vessels are given off, arranged in a net- work with tol- 

 erably regular, oblong, rectangular meshes, their long diameter following the 

 direction of the fibres. These envelop each primitive fasciculus, enclosing 

 it completely, the artery and vein being upon the same side. The capillaries 

 are smaller than in any other part of the vascular system. 



The arrangement of the lymphatics in the muscles has never been defi- 

 nitely ascertained. There are lymphatics surrounding the large vascular 

 trunks of the extremities and of the abdominal and thoracic walls, which, it 

 would appear, must come from the substance of the muscles ; but they have 

 never been traced to their origin. Sappey has succeeded in injecting lym- 

 phatics upon the surface of some of the larger muscles, but he has not been 

 able to follow them into the muscular substance. 



Connection of the Muscles with the Tendons. The primitive muscular 

 fasciculi terminate in little, conical extremities, which are received into corre- 

 sponding depressions in the bundles of fibres composing the tendons ; but 

 this union is so close that the muscle or the tendon may be ruptured without 

 a separation at the point of union. In the penniform muscles this arrange- 

 ment is quite uniform. In other muscles it is essentially the same, but the 

 perimysium seems to be continuous with the loose areolar tissue enveloping 

 the corresponding tendinous bundles. 



Chemical Composition of the Muscles. The most important nitrogenized 

 constituent of the muscles is myosine. This resembles fibrin, but it presents 

 certain points of difference in its behavior to reagents, by which it may be 

 readily distinguished. One of its peculiar properties is that it is dissolved 

 at an ordinary temperature by a mixture of one part of hydrochloric acid 

 and ten of water. The muscular substance is permeated by a fluid, called 

 the muscular juice, which contains certain coagulable albuminoid substances. 

 Combined with the organic constituents of the muscular substance are min- 

 eral salts in great variety, which can not be separated without incineration. 

 Certain excrementitious matters have also been found in the muscles ; and 

 probably nearly all of those eliminated by the kidneys exist here, although 

 they are taken up by the blood as fast as they are produced and are conse- 

 quently detected with difficulty. The muscles also contain inosite, inosic 

 acid, lactic acid and certain volatile acids of fatty origin. During life the 



