354 MUSCLES. 



right angles, lateral filaments, which penetrate between the fas- 

 ciculi and fibres of the muscles, and may be traced to the top 

 of the undulations formed in the muscular fibres. These lateral 

 filaments at some places are two in number, which pass at some 

 distance from each other, but parallel, and terminate by an 

 interchange of fikments; at other places the terminating 

 branches are spread out transversely to the muscular fibre, 

 and end by forming loops with themselves. According to this 

 view, the nervous filaments, strictly speaking, have no termi- 

 nation, but run again into the source from which they are de- 

 rived. 



The chemical analysis of muscles shows them to be com- 

 posed of fibrine, albumen, gelatine, extractive matter, the phos- 

 phate of sodst, ammonia, and of lime, and of the carbonate of 

 lime. The extractive matter of the muscle may be removed 

 by maceration in clean water, often changed. If it be allowed 

 to remain long, it assumes certain appearances in its putre- 

 faction peculiar to itself, but occasionally it is converted into a 

 substance resembling spermaceti. When* a muscle is exposed 

 to boiling water, the albumen is raised to the surface, like 

 foam; the gelatine coagulates when the muscle is cold; and the 

 fibrine appears as a fibrous grayish substance, insoluble in hot 

 water, closely resembling the irbrine of the blood, and evolv- 

 ing large quantities of nitrogen by the action of nitric acid. 

 When a muscle is exposed to the fire alone, as in roasting, 

 the albumen is hardened; the gelatine is melted, and runs oflf, 

 in part, with the juices of the meat: the extractive matter is 

 that which gives a dark colour to the outside; the fibrine is 

 cooked in the juices of the meat, and is then rendered very 

 tender. The muscular parts of animals are amongst the easiest 

 of digestion. 



The muscular system of the embryo is first of all in a 

 gelatinous state, and confounded with cellular substance^ 

 but at two months from conception, the fibres are distinct, 

 and at four they begin to contract and to execute different mo- 

 tions. 



The muscular system is subject to varieties of conformation. 



Hobust, muscular individuals frequently have supernumerary 



. muscles and supernumerary heads to their muscles, particularly 



