346 INHIBITION BY EXCITATION AND 



curare, without however discovering- any difference when the 

 curare was dispensed with. The muscle, with the two stumps 

 of bone left attached to it in the usual way at both ends, was then 

 stretched immovably in a horizontal position before it was excited : 

 the lower thin end had been previously dipped up to about 5 mm. of 

 its length for 5 to 10 minutes in a o-6/ solution of common salt, 

 in which ooi-oo3 / of acetate of veratrine had been dissolved. 



It is of special importance in these experiments to make it a 

 rule to choose only preparations, the muscles of which look in- 

 tensely red, as otherwise one cannot count on perceiving- the 

 phenomena resulting from the excitation with complete and con- 

 vincing clearness. 



When the end of the muscle is dipped into the solution of 

 veratrine, contractions occur generally after a time ; these are best 

 prevented by a slight weighting of the muscle as it hangs vertically, 

 so as to prevent other points of the surface besides the tract which 

 is immersed from coming into contact with the solution. 



Notwithstanding the fact that the veratrine solution is so very 

 dilute it may still act so as to excite the muscular substance chemi- 

 cally, bringing about a persistent contraction of the immersed tract 

 of muscle which often lasts after the time of immersion and occurs 

 even in the best preparations. In this case, by leading off from the 

 lower end and a point corresponding to about the middle of the 

 muscle, a strong ascending action current is at once observed and it 

 only gradually passes away. To exclude this, and also for reasons 

 which shall be given later, I found it advisable not to make the 

 polarisation experiment directly after removing the muscle from the 

 solution, but only after leaving it for some time ($ hour and longer) 

 in a physiological solution of common salt. 



As I have already remarked, the very characteristic action of 

 veratrine, in contrast with the changes effected in muscle substance 

 by treating locally with potash or soda salts, is not removed even 

 after long continued washing with- indifferent liquids, but persists 

 in almost unchanged strength until the death of the muscle, 

 whether it is poisoned as a whole or only locally. If the muscle 

 has not been injured in the preparation, and if the negativity, 

 occurring as a result of whatever persistent contraction of the 

 veratrinised part there may be, has been got rid of by leaving 

 it for some time in a 0-6% solution of common salt, then, provided 

 that the muscle has been very carefully stretched out, no appre- 

 ciable differences of tension can be observed between the poisoned 



