338 NATURAL SCIENCE [November 



their force, to bring the wave forth. (Experiments of Du Bois-Bay- 

 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 from 

 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.) 



1 5. 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 Centaurcae 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. 1 



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 gr. merely, is 

 enough to determine their immediate motion. 2 



17. Mr Kiihne has succeeded in the construction of a kind of 

 artificial muscle by stuffing a fragment of Hydrophilus' intestine 3 

 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 important 

 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 Clans, Traite de Zoologie. 1884, p. 14. 



2 Lubbock. La vie des plantes, p. 6. 



3 Witb nerves and muscles ! 



