PROTOPLASMIC, AMCEBIC, AND OTHER MOVEMENTS 323 



several compartnaents of the mammalian heart open and close spontaneously by centrifugal and centripetal wave 

 movements ; how the left ventricle of the heart opens and closes as apart from irritability and stimulation of 

 every kind ; how the left auricle is inadequate to forcibly open the left ventricle ; how there is a position of rest 

 for the sarcous elements and the muscles of the heart ; how the left ventricle opens or dilates when it acts outside 

 or beyond the position of rest, and how it closes or contracts when it works within the position of rest ; how these 

 result/S are obtained by centrifugal and centripetal co-ordinated, independent movements, &c. 



Fig. 1. — Shows the voluntary muscular fibres in various degrees of contraction according to different authors. The italic 

 letters indicate the same things in the figures from A to T inclusive. Thus a, means hemisphere of chromatin ; /), Bowman's ele- 

 ments ; (J, clear segment proper ; d, Dobie's elements ; /, Flogel's elements ; h, Henson's line ; i, intermediate segments ; n, inter- 

 mediate nodal line. 



A, B, C, D, E, F. Semi-schematic representation of portions of fibrils of crab's muscle, showing the appearances of the fibrillar 

 segments in the several stages from complete relaxation (A) to complete contraction (F). The fibrils thicken and shorten as they 

 contract. 



G. Three fibrils of crab's leg muscle, showing the successive stages from complete relaxation ()•) to complete contraction (i). 

 6 to 6", show the various appearances of Bowman's elements ; d to d", the appearances of Dobie's elements ; / to/^, the appearances 

 of Flogel's elements ; and c, the clear segments proper. 



H. Uncontracted and fully extended fibril of muscle of crab's leg, fixed with absolute alcohol, stained with heliocine, and then 

 treated with acetic acid and glycerine. 6, Bowman's element swollen ; i, intermediate segments not swollen ; c, clear segment, 

 swollen only at end connected with Bowman's element. 



I. Contracted muscle prepared as at H, showing appearance of a bundle of fibrils before addition of acetic acid, h, Bowman's 

 elements ; h, Henson's line. 



J. The same bundle of fibrils as at I, after addition of acetic acid. 



K. Fibrils of muscle of distal segment of pincer claw of lobster uncontracted and extended to full normal length. 



L, M, M, N, 0. Show the successive stages from complete relaxation {I) to complete contraction (o) in the muscle of a crab's leg. 



P, Q, R. Fibrils of muscle of crab's leg uncontracted and extended to full normal length. Flogel's elements seen as granules 

 of chromatin (/). P, is intended to show the effect of shrinkage on clear (c) and intermediate segments (i). Q, shows a fibril 

 unshrunken ; and B, a bundle of fibrils. The drawings are nearly double the size of those at L, M, N, 0. 



S. Flexor muscle of pincer of crab stained with gold chloride. Shows primary bundles of fibrils (6) outlined by longitudinal 

 gold lines, with rounded, deeply-stained particles opposite Dobie's line {d). 



T. Optical transverse section of the same bundles (Rutherford). 



Fig. 2. — Small artery and vein as seen in juxtaposition, with the sarcous and other elements arranged at right angles to each 

 other, a, a. Coats of small artery with sarcous elements arranged longitudinally ; h, similar elements arranged transversely ; f, c, 

 the longitudinal and transverse sarcous elements superposed ; a', a', coats of small vein with sarcous and other elements arranged 

 longitudinally ; V, sarcous and other elements arranged transversely or at right angles ; c', <:', the longitudinal and transverse 

 elements superposed (after Huxley). 



Fig. 2 illustrates the mechanism by which small blood-vessels (arterioles) are alternately dilated and partially closed — how 

 hollow viscera, such as the heart, stomach, bladder, &c., are opened, and partially or wholly closed ; and how the flexor and 

 extensor, the abductor and adductor, and the pronator and supinator muscles are co-ordinated and work harmoniously in pairs 

 (the Author, 1872). 



Pig. 3. A, B, C, D, E. Diagrams by the Author showing that the sarcous elements of the involuntary and voluntary muscles, 



when in action, are arranged at right angles to each other, and that they are endowed with waved centripetal and centrifugal 

 movements, whereby they reverse and change their shapes when the muscles contract or shorten, and when they relax or elongate. 

 The sarcous elements, when in action, are always arranged in two sets— a vertical or longitudinal, and a horizontal or transverse ; 

 and the two sets are co-ordinated and work harmoniously together. In the case of arterioles (small arteries), where there are two 

 layers of involuntary muscular fibres (a vertical or longitudinal layer, and a horizontal or transverse layer), the sarcous elements, 

 which are spindle-shaped, are arranged symmetrically at right angles as at A. In this figure the vessel is represented at rest, that 

 is, neither dilating or contracting. AVhen the vessel is dilating as at B, the vertical or longitudinal sarcous elements swell out and 

 shorten, while the horizontal or transverse sarcous elements narrow and elongate. When the vessel is closing and reducing its 

 calibre as at 0, a reverse movement takes place ; the vertical or longitudinal elements narrowing and elongating, and the horizontal 

 or transverse elements swelling out and shortening. The two sets of movements referred to alternately diminish and increase the 

 length of the arteriole. ■ , c 



The sarcous elements in voluntary muscles are square or cube-shaped when at rest. When in action, they form elongated, 

 square-shaped bodies, which are arranged at right angles to each other as at D and E. The pecuharity of the sarcous elements of 

 the voluntary muscles, as of the involuntary ones, consists in their power of changing shape in two directions ; the same sarcous 

 element elongating transversely or across the muscle the one instant, and longitudinally or m the direction of the length of the 

 muscle the next. This produces an alternating spindle-shaped arrangement of the individual fibrilte of the muscle, and a waved 

 movement of the muscle as a whole. 



The sarcous elements of muscles, and the muscles themselves, are never opposed to each other; they always act con- 

 sentaneously and harmoniously. When one sarcous element, or the muscle to which it belongs, thms and elongates in one 

 direction, its counterpart or fellow thickens and shortens in an opposite direction. There is no such thing as antagonism, m the old 

 sense, in muscular action. The flexors do not forcibly drag out the extensors in flexion ; neither do the extensors forcibly drag 

 out the flexors in extension. The same is true of the abductors and adductors, and of the pronators and supinators. When the 

 ventricles of the mammalian heart contract or close, the sarcous elements of the ventricular muscles act simultaneously and 

 exercise their centripetal power; when the ventricles dilate or open, the sarcous elements exercise their centrifugal power. The 

 same is true of the sarcous elements of the auricles. The auricles close when the ventricles open, a,nAmce versd, but the moveinents 

 are independent of each other, and the one does not cause the other. The centripetal and centrifugal power is necessary to all 

 muscular action It is exerted by the hollow viscera with sphincters (the stomach, bladder, uterus, &c). In these cases, when the 

 muscles forming the bodies of the viscera are in an active state and contract or close, the muscles forming the sphincters dilate and 

 open. When the viscera are at rest their cavities are open and the sphincters closed i v, ■ • ^u • 



The power of acting in two directions inheres in both the involuntary and voluntary muscles, and likewise in their sarcous 

 elements (the Author, 1872). 



