180 



THE MUSCLES. 



Fig. 98. 



1. Tendons may pass in the same direction as the muscular iibres. This 

 is the most simple manner. But the muscle may be divided into two bodies 

 or bellies by a middle tendon ; it is then called a digastric muscle. 



2. Muscular fasciculi, passing altogether from the same side to become 

 anited into a tendinous cord, constitute a semi-penniform muscle. 



3. Muscular fasciculi may be implanted to right and left of the tendon, 

 and form a pennated or penniform muscle. 



" This arrangement of fibres demonstrates that the length of the muscle, 

 the length of its belly, and the length of its muscular fibres, should be care- 

 fully distinguished. The first term is applicable to the whole of the muscle, 

 the tendon included ; the second, to the fleshy body of the muscle, with the 

 exception of the tendon ; the third, to the muscular fasciculi constituting 

 this fleshy body : the latter idea is the most important, for it alone indicates 



the amount of contraction a muscle is sus- 

 ceptible of, and consequently the possible ex- 

 tent of movement it is capable of effecting." — 

 Beaunis and Bouchard. 



C. Vessels and Nekvbs. — The muscular 

 tissue receives much blood ; the fibrous tissue 

 very little. The arteries are large, numerous, 

 and each is acccompanied by two veins. The 

 capillary vessels anastomose in such a manner 

 as to form rectangular meshes, whose greatest 

 diameter is directed towards the length of the 

 muscle. 



The lympTiatic vessels of the muscles are 

 few ; they sometimes penetrate their interior in 

 following the capillaries ; at other times they remain on the surface, in the 



external perimysium. The exist- 

 ence of lymphatics has not yet been 

 demonstrated in tendons, aponeu- 

 roses, or synovial membranes. 



The nerves emanate from the 

 cerebro-spinal centre. At their 

 terminal extremity they offer a 

 small enlargement, called by 

 Eouget the terminal motor plate, 

 and by Doyere and Kiihne the ner- 

 vous colling (hillock). It is ad- 

 mitted that the motor tube traverses 

 the sarcolemma, losing its enve- 

 lope ; and that the substance of the 

 cylinder is spread over the surface 

 of the muscular fibrillse to form the 

 motor plate or nervous coUine. 



mSTEIEUTION OF CAPILLARIES 

 IN MUSCLE. 



Ym. 99. 



?^ 



PORTION OF AN ELEMENTARY MUSOtTLAR FIBRE, 

 WITH FOUR DARK-BORDERED FIBRES (a) CROSS- 



INO ITS SURFACE ; after Beale. 

 b, Capillary blood-vessel, with fine nerve-fibres ; 

 a few only of the transverse markings of the 

 muscle are represented ; c, Two of the dark- 

 bordered nerve-fibres passing over the ele- 

 mentary fibre to be distributed to adjacent 

 fibres. This arrangement, in which a dark- 

 bordered nerve-fibre, distributed to muscle, 

 divides into branches, one of which passes to 

 a vessel, while the other ramifies upon a 

 muscle, is frequent. Magnified 700 diameters. 



PHYSICO-CHEMICAL PEOPEBTIES OF 

 STEIPED MUSCLES. 



Muscles are soft organs, re- 

 markable for their more or less 

 deep-red colour, which varies with 

 the species, and even in these with 

 the age and health of the animals. 



