246 Double Conduction in the Central Nervous System. 



law of the "polarisation dynamique des nevrons" put forward by 

 Ramon-y-Cajal* and V. Gehuchten.t It offers, however, no contra- 

 diction to what JamesJ has termed " the law of forward direction ;" 

 it only emphasises that that law predicates the existence of at least 

 two links in its conduct ion-gear. 



The reaction is therefore in my view an extreme illustration of 

 double (antidrome, doppelsinnige) nervous conduction. After du 

 Bois' fundamental observation with frog's sciatic and the electrical 

 sign, it has been Kiihne's sartoHus experiment^ and Babuchin'sj| 

 reversed discharge in the electric organ nerve-fibre, which have laid 

 a satisfactory foundation for double conduction in peripheral nerves. 

 But between those experiments and these, the subject of this note, 

 there are, it is true, differences. In the latter, («) propagation occurs 

 over relatively huge distances and the reaction occurs within 

 the field of the central nervous system. These differences need not, 

 however, negative the relationship of the phenomena. They render 

 it the more instructive. 



It is obvious that there must be opportunity for detection of anti- 

 drome conduction in parts of the central nervous system besides the 

 dorsal spinal columns. Thus, on exciting, especially with electric 

 currents, the mammalian metencephalon {vermis cerebelli) and isthmus 

 rhombencephali,% subsequent to ablation of the parts above, I have 

 seen movements produced in the limbs and trunk, and also inhibitions 

 occur. Thus, in instance of the latter, inhibition of the tonic extensor 

 spasm of the fore and hind limbs combined with contraction of the 

 flexors of knee and elbow, such as is seen under local spinal reflex 

 action.** It will have to be determined whether in such cases as 

 the former we have not before us instances of antidrome conduction 

 along ascending paths. The antidrome phenomenon, while of valuable 

 assistance when recognised, may, if unrecognised, give rise to very 

 misleading inferences. Its methodic use should place in our hands a 

 fresh instrument of value for neurological research. 



# 1 Medicina practica,' 1889 ; ' Reyista de Ciencias Medicas de Barcelona,' Xos. 21 

 and 22, 1S91. 



t ' La Cellule,' vol. 7, p. 101, 1891. 



X ' Psychology,' and cf. Waller, ' Science Progress, 5 vol. 3. p. 186, May, 1895. 

 § ' Arch. f. Anat. u. Physiol.,' 3859, p. 595. 

 II Du Bois-Eeymond's < Arch, f . Physiol.,' 1877, p. 68. 

 % Sherrington, 'Roy. Soc. Proc.,' yol. 60, p. 414. 

 # * Sherrington, ibid. 



