140 ON NEKVE-EXCITATION BY THE NERVE-CURRENT. 



disappearing. If I now lowered the vessel, the tetanus increased, 

 and was again at its maximum when the surface of the fluid was 

 i cm. above the injured part. Further lowering of the vessel 

 caused diminution of the tetanus, and finally its disappearance 

 when the fluid was no longer above the crushed point. I could 

 repeat this observation several times with the same preparation. 



In by far the greater number of trials this experiment did not in- 

 deed give such evident results ; at the moment that the nerve current 

 is closed through the fluid a clonic agitation of the preparation 

 occurs which soon disappears, or else the experiment is successful at 

 the first trial only, or not at all. But in such cases even one may 

 still get a reaction if the fluid is raised as rapidly as possible ; a 

 closure contraction then follows, as is generally the rule whenever 

 the nerve-current of a moderately excitable preparation is suddenly 

 closed externally. 



According to previous observers \ a reaction of the nerve-muscle 

 preparation cannot be obtained if the transverse section is con- 

 nected with a point of the longitudinal surface as near to it as 

 possible. I have repeatedly succeeded in obtaining contraction 

 under these circumstances, because I used preparations which were 

 disposed to fall into tetanic excitation. If I made the experiment 

 as soon as the preparation entirely ceased to contract in conse- 

 quence of the freshly made section, and taking care to avoid any 

 wetting of the nerve, the making contact between transverse and 

 longitudinal sections gave me strong clonic agitation of particular 

 groups of muscles. Moreover, I can point to instances in which 

 there occurred strong closure contraction followed by clonic agita- 

 tion, provided I had been able to establish contact with sufficient 

 rapidity, rather a difficult matter here. 



The same holds good for an experiment which was made by 

 Galvani, and which du Bois-Reymond designated as the fundamental 

 experiment in the electro-physics of nerve, although he was not 

 very successful in its repetition. * Galvani arranged the nerve of 

 a galvanoscopic leg as an open loop, and allowed the nerve of a 

 second and otherwise completely isolated leg to fall upon the first 

 nerve in such a way that the transverse section of the first nerve 

 constituted one of the two points of contact. In favourable cases 

 both legs contracted V In speaking of the excitation of muscle 



1 See du Bois-Reymond, Unters. Uber thier. Elektr. ii. p. 272, and Kiihne, 

 loc. cit. 



2 Du Bois-Reymond, Unters. liber thier. Elektr. i. p. 273. 



