SECT. 87.] MUSCULAR SYSTEM. l6l 



with the exception of the tongue, heart, and certain respiratory organs (Bar- 

 delehen), the elements, according to Mepp and Wed I, appear simply to increase 

 in thickness ; and, according to the former, the hypertrophied fasciculi in the 

 heart are four times larger than the normal. A true atrophy takes place in 

 old age. The fibres are then narrow, some only 0-004'" to 0-008'" in dia- 

 meter, friable, and, for the most part, without transverse striae and with 

 indistinct fibrils. They often contain a large number of yellowish or brown 

 granules and numerous vesicular nuclei with nucleoli, which are often ar- 

 ranged in linear series, or collected in heaps upon the inner side of the sarco- 

 lemma ; and, singularly enough, exhibit the same indications of an energetic 

 multiplication by endogenous formation, as in the embryo. Besides these, 

 many other pathological processes accompany atrophy of the muscles. In 

 tin formation of fat in the muscle*, which often occurs in the heart, the mus- 

 cular fibres are gradually displaced by connective tissue and fat-cells developed 

 between them; whilst in their fatty degeneration, the fibrils gradually dis- 

 appear, fat-granules being developed in their place, for the most part in 

 linear series ; or even fat-cells are formed within the sarcolemma. At the 

 same time, the muscles become softer, paler, and more yellowish, and the 

 fibres readily break down. Paralysed muscles were found by Reid to be 

 thinner, suffer and paler, and by Valentin, to have indistinct transverse striae. 

 More recent observers have found in such muscles, for the most part, atrophy 

 with fatty degeneration. 



In emaciated individuals, the muscles are pale and soft, and the fasciculi 

 small. The muscular fibres sometimes, though rarely, become calcified, so 

 that the muscles split up like asbestos. Ossification of a muscle, as some- 

 times happens in the deltoid, from pressure of the musket in military exercise 

 (the so-called Exercirknocheri), arises in the connective tissue, which may 

 also occasion a fibrous metamorphosis of the muscle by its undue increase. 

 In cancer of the pectoralis major, I found the sarcolemma filled with beautiful 

 rows of pale nucleated cells. Of parasites, may be mentioned the Cysticcrcus 

 celhdosee, which lies between the fasciculi, and Trichina, spiralis ; further, a 

 nematoid worm, which Bowman {Cyclop, of Anat., ii., p. 512) saw living in 

 the almost empty sarcolemma of the muscles of the eel. Organic formations 

 — but whether of vegetable or animal nature, is uncertain — are found in 

 rats and mice, as white streaks of 4'" to 7'" long, and 0-09'" to o'i'" broad, and, 

 on microscopical investigation, seem to be hollo m primitive fasciculi filled with 

 elliptical, slightly curved corpuscles, of 0-004"' to 0-005'" long, and 0-0019'" 

 broad, resembling eggs. 



§ 87. Physiological Remarks . — The most conspicuous property 

 of the muscles is their contractility. In contraction, the fibres 

 shorten themselves rectilinearly, and, at the same time, become 

 thicker, but without any notable increase in density. Probably 

 the contraction, as a rule, takes place contemporaneously in all 

 parts of a fibre, although it is possible that contraction may begin 

 in the parts where the nervous terminations are situated, and 

 precede, though by a space of time immeasurably short, or at 

 least inappreciable to the eye, that of the rest of the fibre. In 



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