PN MUSCULAR MOTION. QQl 



The pl)ials were all corked, and the temperature of ilieir 

 -ontents was 46*'. 



The limb conlained in the phial No. 1, after remaining 

 twenty minutes, had acquired a pale red colour, and the 

 mufcles were highly irritable. 



The limb in No. 2, after the fame duration, had be- 

 come rigid, white, and fwollen ; it was not at all irritable. * 

 Py removing the limb into a diluted folution of vegetable 

 pikali, the mufcles were relaxed, but no figns of irritability 

 returned. 



No. 3, under all the former circumftances, retained its pre- 

 vious appearances, and was irritable, but lefs fo than No. 1, 



No. 4 had become rigid, and the final contradion had taken 

 place. 



Other caufes of the lofs of mufcular irritability occur in Mufcular irrita- 

 pathological teflimonies, fome examples of which may not be ^jlity deftroyed 

 ineligible for the prefent fubje6l. Workmen whofe hands are 

 unavoidably expofed to the conta^ of white lead, are liable 

 to what is called a palfy in the hands and wrifts, from a tor- 

 pidity of the mufcles of the fore arm. This afFe6lion feems 

 lo be decidedly local, becaufe, in many infiances, neither 

 the brain, nor the other members, partake of the diforder ; 

 and it ofteneft affedls the right hand. An ingenious pra6lical 

 chemift in London has frequently experienced fpafms and 

 rigidity in the mufcles of his fore arms, from afTufions of 

 nitric acid over the cuticle of the hand and arm. The ufe 

 of mercury occafionally brings on a fimilar rigidity in the 

 .mafleter mufcles. 



A fmaller quantity of blood flows through a mufcle during Lefs blood flows 

 the ftate of contradion, than during the quiefcent ftate, as t'^rough a con* 

 It. 1 1 ririi ^. trafted mufdc. 



is evmced by the pale colour ot red mulcles when contraded. 



The retardation of the flow of blood from the veins of the fore 

 arm, during vensefedion, when the mufcles of the limb are 

 kept rigid, and the increafed flow after alternate relaxations, 

 induces the probability, that a temporary retardation of the 

 blood in the mufcular fibrils takes place during each con- 

 traction, and that its free courfe obtains again during the re- 

 laxation. This ftate of the vafcular fyftem in a contracted 

 mufcle, does not, however, explain the diminution of its 

 bulk, although it may have fome influence on the limb of a 

 living animal. * 



When 



