168 BEPORT— 1866. 



Last year, when treating iipon the question of rigor mortis, I drew the 

 attention of the Section to a form of muscidar contraction induced in cold- 

 bloods by the irritant action of such vapours as ether, chloroform, bisulpliuret 

 of carbon, amylene, &c. I pointed out that they were the most extreme 

 forms of contraction of which these muscles were capable. The persistent, 

 in most cases permanent character of the contraction at once associated it 

 with the forms of tetanus induced by water of certain temperatures and by 

 the discharge from Ruhnikorft'''s coil. The extreme delicacy of this mode of 

 exciting muscular contraction by ethereal vapours has enabled me to perform 

 some very interesting and instructive experiments. 



I have succeeded in proving, by experiments in which the nervous 

 system has, as far as possible, been removed, and, better still, by experiments 

 on isolated muscles, (1) that both chloroform and warm water act directli/ 

 vpon and produce universal contraction of the muscular tissue, which, accord- 

 ing to the circumstances of its induction, may or mail not he permanent ; (2) that 

 when the nervous and vascular systems are present they complicate the 

 result, and furnish us with illustrations of most important physiological prin- 

 ciples. 



Taking first Tiieemal Tetaxfs, I find two normal limbs ((. e. supplied with 

 both blood and nerve-influence) contract simultaneously. Two limbs de- 

 prived of both blood and nerve-influence also contract simultaneously. Of 

 two limbs, the one having neither nerve nor blood, and the other both nerve 

 and blood, the latter contracts first. Of two limbs, the one having 

 neither nerve nor blood, and the other blood only, the former contracts fu'st. 

 In CnLORoroKJi Tetaxus the same holds good as in the first two examples 

 of thermal tetanus ; but of two limbs, tlie one having neither blood nor nerve, 

 and the other having both blood and nerve, the former contracts first. Of 

 two limbs, the one having neither blood nor nerve, and the other nerve 

 but no blood, the latter contracts first. 



An analysis of these various results shows that both v»'arm water and chlo- 

 roform exercise an excitant action upon the nervous system of the frog, 

 which tends in both cases in the direction of muscular contraction, but which 

 of itself alone is too weak to bring about such an affection of muscle, and, 

 further, that the warm water is more powerfid in this respect than the chlo- 

 roform. It also aftbrds evidence of the important i)rinciple, that certain 

 elements of the blood in the interstices of the muscular tissue oppose a 

 powerful obstacle to such agencies as tend to throw muscular tissue into a 

 state of contraction. 



Mxiscle when dynamically perfect is related, on the one hand, to certain 

 stimuli, as nerve and external agents, which tend to induce contraction, and, 

 on the other, to some of the elements of blood, which bring about its elongation ; 

 but its degree of proneness to fall into contraction appears to be directly pro- 

 portionate to the amount of force generated in it by the blood — in other 

 words, to its irritability ; and although the galvanometric evidences of the 

 existence of force are masJced during contraction by the derived electro- 

 motor currents taking on the negative variation, yet this by no means 

 proves (as some suppose) tliat the hlood-gcneratcd forces are absent; for we 

 have previously seen in explaining Scquard's experiment that the contractive 

 energy, i. e. the tendency of the molecules of muscles to approach each other, 

 may be increased two-and-a-half times, which is at once proof that they do 

 not approach by virtue of any lyermanent force which they possess as mere 

 physical atoms ; for such force would be a fixed and not a varying quantity. 

 It is evident therefore that both the power of contraction and of elongation 

 is derived from the blood; and not the elongating force alone; and we must 



