SECT. 77-] MUSCULAR SYSTEM. 1 43 



in rows, or alternately one behind the other. Besides, very minute 

 and pale granules (the interstitial granules as I have called them) 

 are always met with around the nuclei and between the fibrillar, in 

 regular rows, which., in abnormal muscular fibres, are transformed 

 into the well-known fat and pigment globules (fig. 64) . 



The form of the muscular fibres is rounded-polygonal. In 

 diameter they vary from 0005" to 0-03"', and more. In the trunk 

 and extremities, they are, without exception, thicker (o , oi6'" to 

 0-03'") than on the head, in which situation the muscles, especially 

 those of the face, are distinguished bv the smallness of their 

 fibres (0-005'" to o , oi6 / "). It is to be observed, however, that great 

 differences often prevail, in this respect, in one and the same 

 muscle. As far as is known, there is no absolute difference in the 

 thickness of the muscular fibres in men and women, or in weak 

 and robust individuals. On the other hand, it is possible that in 

 one case the one extreme, and in another the other, may prevail. 

 The thickness of the primitive fibrils in man amounts, on an 

 average, to 0-0005'": their number in a fibre must, in the thicker 

 ones, amount to several hundreds, but it is not known with cer- 

 tainty. 



Various controversial opinions still prevail, as regards the composition of 

 the muscular fibres. Several authors, above all, Bowman, are of opinion, or 

 at least consider it as probable, that the fibrils are artificial products. 

 According to the last-named author, a breaking up of the muscular fibres 

 into discs (fig. 65) is quite as natural, although not quite so frequent, as that 

 into fibrils; and they may with equal justice be held to be columns of discs, as 

 bundles of fibrils. Were a muscular fibre broken up in the direction of both 

 the transverse and longitudinal strise, small, roundish-angular particles would 

 be produced, which might be designated primitive particles, or sarcous 

 elements. In the muscular fibre, these elementary particles are united in the 

 transverse, as well as the longitudinal direction, and form, in the one case a 

 disc, in the other, a section or joint of the fibrillge. The breaking up into 

 discs could, in my opinion, be considered of importance only if it occurred 

 as frequently as that into fibrils and also took place occasionally in fresh 

 muscles. But nothing of the sort is to be seen in the fresh muscles of man 

 and the higher animals. It is rare, even, in macerated fasciculi; while, on 

 the other hand, the fibrils can be isolated in almost every muscle, by any one 

 moderately conversant with the matter. 



In transverse sections of fresh-dried or fresh muscles of the frog, the trans- 

 • sections of the tibrillae can be distinctly seen, which fact refutes all 



ose opinions according to which the muscular fibres, during life, consist of 

 a homogeneous, solid or fluid substance. Moreover, it may be remarked, that 

 the assumed elementary particles can only be isolated with difficulty, except 

 in macerated muscles, where their separation is undoubtedly easy ; and also, 

 that in the perfectly fresh muscles of certain insects (coleoptt ra, in uroptera, 



