STRUCTURE OF MUSCULAR FIBRES. 285 



the adhering extraneous substances, and viewed in a powerful 

 microscope, is a solid cylinder, formed of a pulpy substance, 

 irregularly granulated, and covered by a portion of the regular 

 membrane. 



The opinions of Sir A. Carlysle, are not at the present time, 

 deemed of much weight in anatomy ; subsequent researches 

 having shown them to be full of empty and reckless speculation. 

 Among those who believed the muscular fibre to be hollow, were 

 Sink and Mascagni ; the latter considered it as formed of little 

 cylinders, the walls of which are composed of absorbent vessels 

 and filled with a glutinous substance. More recently, Raspail 

 (Chimie Organique) has adopted a view which appears a 

 modification of, and no better founded than that of Mascagni. 

 He considers each fibre formed of a bundle of cylinders, the 

 cylinders made up of elongated vesicles, attached end to end, 

 and having a spiral arrangement. 



The connexion of these fibres with the blood-vessels and 

 nerves, is an important circumstance in the structure of 

 muscles. 



The arteries of muscles are very numerous ; and they ramify 

 minutely. They are accompanied by veins; and it appears, by 

 the successful labors of Ruysch, that when these arteries are 

 fully injected, they not only communicate with the veins, but 

 also pour out some of their contents in a dew-like effusion in the 

 muscle.* 



With the exception of some of the viscera, as the lungs and 

 kidneys, there are few organs that receive as much blood as the 

 muscles. 



The arteries that supply the muscles, enter them at all points. 

 The larger trunks more generally enter at the middle of the 

 muscle, and ramify towards each extremity, the branches being 

 placed between the larger fasciculi or lacerti, so that the flow 

 of blood, may be less impeded during muscular contraction ; 

 minute branches only passing into the structure of the fasciculi. 



* See Ruysch's description of the 96th preparation in his Thesaurus Quartus ; 

 and of the 35th preparation in Thesaurus Decimus, 



