J90 OV MUSCULAR MOTIOJir, 



cidate any one of the fubjeds propofed, neverlhelcHj I fhall 



not efteern my labour ufelefs, or the time of the Royal Society 



altogether gnprofitably confumed, ill fucceed in pointing out 



'' the way to the future attainment of knowledge fo deeply in- 



terefting to mankind* 



The mufcle it- The mufcular parts of animals are mofl frequently com- 



felf IS fibrous, pofed of many fubliances, in addition to thofe which are purely 



mufcular. In this grofs ftale, they conftitute a flexibJe, com. 



preffible folid, vvhofe texture is generally fibrous, the fibres 



being eompficted into fafciculi, or bundles of various thicknef?^ 



Thefe fibres dre elaftic during the contrafted flate of mufcleif 



after death, being capable of extenfion to more than one-fifth 



of their length, ahd of returning again to their former ftate (jf 



qontradhon. 



TIjc enveldpjng This elaftieity, however, appearii to belong tdthe enveloping 



flKmbraoe is reticular or cellular metnbrane, and it may be fafely aflumed 



th^t the intrinfic matter of mufcle is not elaftic. 



,^ Xheattra6lion of cohefion^ in the parts of mufcle, is ftrongeij 



in the dire6tion of the fibres^ it being double that of the i;Qti^ 



Irary, or tranfverfe diredlion. 



Mufcles are Ir- • When mufcies are capable of reiterated contra6liotis and 



rjtable during relaxations, they are faid to be alive, or to pofiefs irritability^ 



• * This quality fits the organ for its funftions. Irritability will be 



confidered, throughout the prefent ledure, as a quality only. 



They have lefs When mufcles have ceafed to be irritable, their cohelive 



tohefion length- attra^ion in the direftion of their fibres is diminifhedi but i^ 



ways when remains unaltered in the tranfverfe direflion. 



dea4» 



Experiment In ^^^ hinder lirnbs of a fiOg attached tb the pelvis beln^ 



proof. llripped of the tkin^ one of them w^s immerfed in water ^t 



H5° of Fahrenheit, during two minutes, when it ceafed tqi 

 J)e irjhtable. The thigh bonnes were broken in thfe middle^ 

 wiliiout injuring the mufcles, and a feale affixed to the ancle 

 of each limb: a tape pafled between the thighs was emplo}e4 

 to fufpend the apparatus. >7eights were gradually introduceci 

 into each fcalc, until, vjtli five pounds avoirdupois, the dead 

 thigh was ruptured acrofs the flefliy bellies of its mufcles. 

 Tli^ ^rrilable thigh fuflained fix pounds weight avoirdupois^ 



xepeated. and w;is jmptured in the fame manner. This eJcperlment w^? 



repeated on other frogs, vi'here one limb had been killed by g 

 watery folution of opium, and on another where etfenlial oil 



Of 



