Double Conduction in the Central Nervous System. 243 



Double (Antidrome) Conduction in the Central Nervous 

 System." By C. S. Sherrington, M.A., M.D., F.R.S., Holt 

 Professor of Physiology, University College, Liverpool. 

 Received February 15, — Read April 8, 1897. 



In a paper presented to the Society last year,* I drew attention to 

 some striking instances of ; ' long conduction" through the bulbo- 

 spinal cord, and among others to the following singular one. If after 

 transection over the bulbospinal axis the funiculus gracilis be excited, 



e. g., at the calamus scriptorius, the excitation evokes movement (con- 

 traction, relaxation) in the idiolateral hind limb. If instead of /. 

 gracilis the funiculus cuneatus be excited the movement (contraction, 

 relaxation) is in the idiolateral forelimb.' The movement in the 

 hind limb is in the monkey usually adduction and flexion of hallux, 

 in the cat flexion of knee, hip, or ankle. In the monkey the forelimb 

 movement is usually flexion and adduction of pollex, often with exten- 

 sion of the other' digits ; in the cat, more usually flexion of elbow 

 with protraction of the shoulder. The movements which occur are, 

 however, various, and I will here only add that those from the 



f. gracilis include the vaginal and anal orifices, the tail, and the 

 abdominal muscles, those from /. cuneatus the diaphragm ; but that 

 neither from /. gracilis nor /. cuneatus have I obtained idiolateral 

 extension of elbow or of knee. 



In my former paper this phenomenon was recorded under the head 

 of " long bulbo- spinal conductions." I did not offer any explanation 

 of it, for it appeared to particularly require further investigation. 

 I have, since communicating the above paper, taken various oppor- 

 tunities of examining the reaction further. My enquiry has elicited 

 the subjoined results. 



The movements evoked in the perineum or hind limb by excitation 

 of the /. gracilis after transection of the bulb are obtainable from 

 that column, after its isolation, by freeing it above and from its 

 ventrolateral connexions for a length of 3 cm., and then suspending 

 its upper end from a thread. The reaction is therefore hardly due to 

 escape of the stimulating currents used, so that they reach the 

 lateral columns and the descending tracts there contained. The 

 currents employed have been induced, and of an intensity impercept- 

 ible, or barely perceptible to the tongue tip. The electrodes have 

 been bright steel needles, placed about 1 mm. apart, and laid on the 

 surfaces of the cord or bulb. 



* " Experiments in examination of the Peripheral Distribution of the Fibres of 

 the Posterior Roots of some Spinal Nerves, Part II," Abstract, 'Roy. Soc. Proc.,' 

 vol. 60, No. 365. 



