596 MOTION. 



owing to the contraction of the intestinal walls. It is still 

 better shown in the arteries, of which all that have mus- 

 cular coats contract after death, and thus present the 

 roundness and cord-like feel of the arteries of a limb lately 

 removed, or those of a body recently dead. Subsequently 

 they relax, as do all the other muscles, and feel lax and 

 flabby, and lie as if flattened, and with their walls nearly 

 in contact.* 



Actions of the Voluntary Muscles. 



The greater part of the voluntary muscles of the body 

 act as sources of power for moving levers, the latter 

 consisting of the various bones to which the muscles are 

 attached. 



All levers have been divided into three kinds, according 

 to the relative position of the power, the weight to be moved, 

 and the axis of motion or fulcrum. In a lever of the first 

 kind the power is at one extremity of the lever, the weight 

 at the other, and the fulcrum between the two. If the 

 initial letters only of the power, weight, and fulcrum be 

 used, the arrangement will stand thus :-*-P.F.W. A 



* Although the preceding remarks represent the views generally enter- 

 tained in regard to muscular action, yet it must be observed that a new 

 and very different theory on the subject has been lately advanced by 

 several writers, and especially developed by Dr. Eadcliffe, who has also 

 made it the basis of new views on the pathology of various convulsive 

 affections. According to this doctrine, the ordinary relaxed or elongated 

 state of a muscle is due to a certain " state of polarity" in which the 

 muscle is maintained, and contraction is brought about by anything 

 (such as an effort of the will) which liberates the muscle from this 

 influence, and thus leaves it to the operation of the attractive force 

 inherent in the muscular molecules. According to this doctrine, also, 

 the stage of rigor mortis is readily explicable : death depriving the 

 muscles of the " state of polarity " whereby they had hitherto been kept 

 relaxed, and thus allowing the attractive force of the muscular particles 

 to come into play. For facts and arguments in support of this view, 

 and for references and confirmatory opinions, Dr. Radcliffe's work On 

 Epileptic and other Convulsive Affections may be consulted. 



