434 MUSCLE JUICE. 



probably by reason of a twist, tension, or undue strain, a spiral appear- 

 ance is presented ; c, c are the primitive fasciculi. 



A fluid surrounds the fibres of striped muscles, and the fibre cells of 



smooth ones, which is wholly different from the plasma of 



Muscle juice. ^ ^^ The exper i ments O f Schultz show-that this fluid 



contains a large amount of casein, a conclusion of considerable import- 

 ance, since, if there were any doubt of the occurrence of that substance 

 in the blood, this fact, at all events, renders it certain that the mammary 

 gland is not necessary to its formation. That the substance thus occur- 

 ring is casein is proved by the action of rennet. 



Muscle juice undoubtedly arises within the sarcolemma through which 

 it exudes. Each fibre therefore presents four objects : the syntonin, the 

 nucleus, the sarcolemma, and the muscle juice. That the muscle juice 

 arises in part from the functional activity of the fibre, and is immediate- 

 ly derived from the waste of its syntonin, and that, in its turn, the syn- 

 tonin is closely allied to the substance of the nucleus, is shown by their 

 exhibiting almost the same chemical reactions with alkalies, acids, etc. 



The sarcolemma is not, however, filled with syntonin; it contains be- 

 sides, as stated above, a certain quantity of fat, as may be demonstrated 

 by removing from the sarcolemma its syntonin by acids, when a granu- 

 lar material will be left. That this is fat is proved by its solubility in 

 sulphuric ether. 



The sarcolemma does not belong to the protein class of bodies, but is 

 Sarcolem- rather analogous to elastic tissue. The color of muscle appears 

 ma - to be not so much due to the blood as to a special pigment, 



which, perhaps, adheres in a free state to the fibrils. The muscle juice 

 contains relatively far more potash salts and phosphates than the blood, 

 as is shown by the following table from Liebig. 



For one hundred parts of soda there occur, 



In the hen, 40.8 of potash in the blood, and 381 in the muscle juice. 

 " 'ox, 5.9 " " " 279 " " 



" horse, 9.5 " " " 285 " " 



" fox, " " " 214: " " 



" pike, " " " 497 " " 



It is commonly stated that muscular motion is accomplished by fibres 

 Two forms of of .two different kinds: 1st. The simple, non-striated, un- 

 fibre n^n stri P e <^ or organic fibre ; 2d. The striated, striped, or volun- 

 stria'ted and tary fibre just described. Though this subdivision may be 

 convenient, it can scarcely be regarded as accurate, since the 

 former variety passes by insensible degrees during development into the 

 latter, and cases, indeed, are not wanting in which the same fasciculus 

 presents in different parts both conditions at once. 



The non-striated muscular fibre. Fig. 215, consists of translucent bands 



