338 NATURAL SCIENCE _ [November 
their force, to bring the wave forth. (Experiments of Du Bois-Ray- 
mond on the destruction of a nerve by a current of increasing 
intensity.) It is exactly the same with the nerve of mercury: rub 
it roughly with a piece of feather and this excitation will soon be 
answered, but it will remain dumb whenever you rub it slowly and 
gradually with a cloth. 
_ 14. There is transmissibility of the excito-motory vibration fis 
a natural or artificial nerve to another when the latter was not in 
its normal state connected with the former. Their activity can be 
brought about by means of a stimulus, after every communication 
between this organ and the centre of innervation has been completely 
interrupted. (Fig. 5.) 
15. It may be objected that the equilibrium of a liquid is not 
to be altered by such slight vibrations as those that impress the 
human auditive nerve. Audition would then be impossible. More- 
over, the telephone of mercury is established precisely on the principle 
according to which the transmission of vibrations is effected by means 
of mercury, and we here repeat that the liquid veins of Savart were 
modified at the College de France by some music performed at the 
Luxembourg, that was entirely inappreciable to the ear. 
16. The stamens of the Centawreae shrink. up in their whole 
length whenever they are submitted to a mechanical excitation, on 
account of some laws similar to those that rule the contraction of 
muscles in higher animals. 
Electricity affects Sensitives too if discharged in sparks, but it 
seems to have no influence whatever when it works by continuous 
currents. It acts in the same manner on nerves. . 
The sensibility exhibited by the leaves of Drosera is such, that 
an object placed on them and weighing some 000008 ger. merely, is 
enough to determine their immediate motion.? 
17. Mr Kiihne has succeeded in the construction of a kind of 
artificial muscle by stuffing a fragment of Hydrophilus’ intestine? 
with the semi-fluid protoplasm of a certain Myxomycetes. This 
apparatus was affected by electricity as well as if it had been a real 
muscle. There is not a special force, therefore, but only a liquid 
capable of vibration. 
(b) Muscular vibration —I cannot dwell long on the ire sorta 
question of muscular vibration without wandering too far from the 
principal object of the present paper. 
The theory of muscular waves as conceived by Marey and Weber 
has been fully confirmed by the experiments below : 
1. Fix a tube of caoutchouc of small diameter by one of its 
1 Claus, Traité de Zoologie. 1884, y 
? Lubbock. _ La vie des plantes, p: 6 
3 With nerves and muscles ! 
