430 GENERAL ANATOMY. 



remains irritable much longer than any other muscle, by the 

 application of. mechanical agents, and the muscles of the 

 skeleton, on the contrary, by galvanic irritation. Galvanic 

 irritation acts more efficaciously by not comprehending the 

 exterior muscles, than by comprehending them with the nerve 

 in the galvanic circuit. The contrary occurs with the inte- 

 rior muscles. 



The order established by Nysten, with respect to the suc- 

 cessive extinction of irritability in the bodies of decapitated 

 individuals, is as follows: 1st, the aortic ventricle of the heart; 

 2d, the large intestine, the small intestine and the stomach; 

 3d, the urinary bladder; 4th, the pulmonary ventricle; 5th, 

 the oesophagus; 6th, the iris; 7th, the exterior muscles; Sth, 

 the right auricle, and lastly, the left auricle. 



Muscles or parts of muscles, separated from the living body, 

 retain their irritability for some time. They present, in this 

 respect, variations analogous to those which have just been 

 indicated. Contraction under these two circumstances evi- 

 dently takes place without an afflux of blood. 



688. When irritability is on the point of being extinct or 

 exhausted in the muscles, irritation no longer determines any 

 general or extensive contraction of the entire muscles, their 

 bundles or fasciculi; but it remains limited to the points irri- 

 tated, which swell by the flexuosity of which it becomes the 

 seat. This last description of irritability which survives the 

 nervous action, appears to me to be precisely of the same kind 

 as that observable in the fibrine.of the blood; this is in reality 

 the vis insita of the muscular fibre. 



689. The kind of death, the previous state, and the sur- 

 rounding circumstances, exert an influence on the cadaverous 

 irritability. The state of paralyses and of hemiplegia does not 

 prevent the muscles from being irritable in the cadaver, by 

 galvanism. Diseases have a much greater influence on the 

 cadaverous irritability by their progress and continuance, than 

 by their nature; chronic diseases alter'this property much 

 more than acute ones, and among the chijpnic diseases, those 

 in which nutrition is most impaired, are'most fatal to muscular 

 action. The most muscular persons are not those in whom mus- 



